Origins of foot fetish

The foot resembles a phallic symbol, a part of the woman's body that looks like a phallus, it is of the size of phallus, and of the shape of phallus (or maybe the toes are considered phallic symbols for some). Why this part and not her hands, her nose, etc? Because it is considered a bit more intimate body part, not exposed to view all the time and due to this fact, it is more likely to be a phallic symbol, since phallus is intimate as well. Revealing feet is done when two people get more intimate and it is something almost not acceptable under normal daylife social life, in school, in job, in the street etc. So the anticipation to reveal feet can be an analogue of the anticipation of revealing phallus for some. The likelihood to consider the foot as a phallic symbol is increased compared with other body parts, also because it must represent some kind of power. Phallus represents power, thus the phallic symbol must do the same to be a more believable phallic symbol. But how foot can represent power? In many circumstances a person in the feet of another person seems inferior or defeated, so feet can easily be assigned as a symbol of power. Also, the fact that often feet are considered dirty, the lowest part, ignored, etc, placing one at the feet of another, increases the symbolic "defeat" and thus it assignes more power to feet. Kissing feet, washing feet, etc are in many societies symbolic acts of submission as well. Moreover, the visual effect of watching someone from above increases your power to him and the opposite: watching from below (from the foot level) increases the power on you. Furthemore, the fact that feet often are considered smelly, dirty, and children learn to seem them disgustingly, may be a precondition to see it as a phallic symbol, since children also are taught to consider penis as dirty. So all these can be subconsciously proceced in the foot fetishist mind and making the foot satisfying many preconditions to be considered a phallic symbol.

The same goes with shoes, pointy, boots, high heels etc, all resemble phallic symbols, all are strongly associated with feminity, and all are associated with status, power, etc.

Why a man would look for a phallic symbol in women?
When a man starts understands the differences of the sexes, and starts exploring the opposite sex, he is fascinated by two mechanisms. First, his mother gives him love and satisfies his needs, so he craves her (not sexually, but the differences are obscure at that age). Second, having experiences with girls and women, cause him erections (may not be visible at very young age as a full erection, but as penile responses as the sexual centers of the brain are starting to stimulate, by the visual stimulis). As his interested in women begings, his enthusiasm makes him craving women. Also, he maybe considers becoming like them (differences in the sexes are obscure at that age and maybe wanting something is translated to becoming this, as for example liking cats makes a child act like a cat) (transference). The craving of his mother (for satisfying his needs) and of women (for giving him atypical erections) cause enthusiasm which easily and quickly becomes a disappointment, since he cannot have always his mother near or other women. Thus, the first experience of desire of the other sex or of his mother makes him feel dependable. But as the age of the child increases and there is a social demand for independence (his parents teach him to be independent etc) but also a personal need for independence (his ego and egoism are starting to formulate, eg. he starts demanding games, etc), the previous enthusiasm about the mother and women is conflicting with his ego and is experienced as a threat or a cause of disatisfaction (he wants his mother but he can't have her all the time so it is disappointment, her mother often may not satisfy his increasing needs, so it is disappointment, his mother may object to some of his needs, so it is threat, feels compelled from wanting women, so it is threat to his ego). This conflict leads the child to experience the opposite sex as a cause of threat or disappointment (he may wouldn't do so, if he didn't experience his craving for women so intensively, which increased his expectations and thus made his later disatisfaction more intense), which can be called castration anxiety, not of actual castration but a symbolic threat and disappointment from the love object against the masculinity, the ego, the egoism, the self, the satisfaction, the inner peace, the personal choices, etc of the child. In order to alleviate this conflict, as a defense he must find a phallic symbol in women. Subconsciouly the young male when he watches women, he seeks for a phallic symbol on them.

There can be many reasons why a person can seek a phallic symbol in a woman, but it is a pathology to do so anyway, it is a mechanism to alleviate a conflict (not to solve it, as it should be the goal and ofcourse there shouldn't be a conflict at first hand).
First, he may try to find a phallic symbol, because wanting to become like them is later experienced as a threat to his ego and masculinity, so by finding a phallic symbol to women, the transference connection with the woman will be possible (he may "become" a woman) and thus erection is achievable (please note it's about trangender wishes, etc, it is symbolicaly and way of thinking of childs that if they cause conflict and not been resolved they are preserved into the subconscious).
Second, he may need to find a phallic symbol, so that worshipping it, he will make him feel safe that the woman will not leave him, dissatisfy him, disappoint him, threaten his self, etc, and this way by feeling safe, erection is possible. Third, it can relieve the conflict of the threat of the loss of ego, since the woman can have a phallus, a power, when he feels overpowered by his sexual urges, so he will feel safe that someone will protect him. In every way, the erection is the result, which can be due to many things, for example as a defense of the ego, the penis erects in order to stress his masculinity, as a reaction of aggression, as a way of allowing erection since stress, inhibitions, etc are decreased.

Also, worshipping feet could be perceived as a threat to ego, which causes narcissistic rage, that leads to erection from feeling aggression or perceived as causing to him feelings of defeat, which symbolically mean defeat against sexual inhibitions that are supposed to protect ego, and thus triggering erection.

Now the "arguements" foot fetishists use to justify their craving for the foot are just non-senses: they may say that they just love women from head to toe, they may describe the details of the foot as if it is something exceptional, etc. No matter what they claim, their behaviour surely is strange and indicate that a subconscious cognitive process is going on. Worshipping a dirty part of a woman in order to prove his love, etc, is often an indication of perverse sense of love.

For a foot fetish to fully develop, some other factors may be contributing. First, the need to fixate in a specific body part, in order to increase attention, so that erection will be possible. This ofcourse is needed for people that have strong sexual inhibitions and need this kind of fixating in order to get aroused. Second, some may have a need to see first sexually a body part that it is intimate, but not associated with the guilt of normal erotogenous zones (eg vagina, breasts, etc). So seeing foot this way, they become aroused since they decrease the guilt associated with watching other body parts and this helps them become sexually aroused.

Ofcourse, the experiences of each foot fetishist are unique, for example seeing in a movie kissing etc may incline them to foot fetishism. Also, the whole process is too complicated and various factors are different in each foot fetishist, for example the intensity of the disappointment that caused the castration anxiety would be a factor, etc, so each foot fetishist is unique, but the underlying mechanism is the same.