From a psychological standpoint, unconventional interests within families can create tension if not handled with care. A sister's foot fetish, like any niche preference, might initially catch family members off guard, especially if they stumble upon it accidentally. The key is how openly and respectfully everyone communicates about it.
Families thrive on mutual understanding, so if this fetish becomes a point of judgment or secrecy, it could strain relationships. But I've seen cases where siblings bond over shared humor or acceptance—imagine inside jokes about 'shoe shopping trips' instead of awkwardness. It really depends on the family's dynamic. Some might shrug it off as quirky, while others may need time to adjust. What matters is ensuring no one feels shamed or pressured.