Why do people hate it so much when i put my feet on the table?!?!?

i grew up in a friendly, loving and nurturing environment where everyone was carefree and out to live their lives out in the open gentle fields of the countryside. no one verbally attacks me when i put my feet on the table! But since i moved to the big city, i cant do that anymore. I do it at my school, in the car, in restaurants, it is just more comfortable! Does this ever happen to u? Sometimes people just overreact, they scream and they're just uncivilized. More than once i've cried myself to sleep wondering when i will be accepted into society. Is there something wrong with me?