Most commonly I get "You just have them loose in your house?" And "What about your cat/dogs?"
Less common "You feed them mice and stuff?" "Where do you keep them, not in the house??" "You have HOW many?" "Rodents in the fridge/freezer???" "Are they poisonous?" "They'll get 20 feet long".
Usually I tell people I'm more concerned about my 20 lb lizards injuring me than the harmless ball pythons. That usually snaps their brains, and they stop asking.