Imagine you are getting to know someone as a friend -- hanging out with them for the first time. Considering that everything otherwise is going quite well, which of the following things would make you *seriously* question whether you wanted to hang out with him/her again?
a) S/he picks his/her nose and eats it unabashedly in your presence.
b) S/he stares repeatedly at your crotch with an alarmed expression that leads you to think maybe you have spilled something on yourself (which you haven't done).
c) S/he asks to borrow $50 so s/he can buy a pair of sunglasses s/he really likes.
d) S/he describes a really disgusting toilet incident to you while you are eating.
e) As you part, s/he punches you really hard in the chest and says, "See ya, stupid!"