Is it normal for guys to urinate in the bathroom sink?

Answer 1

Where one urinates is determined by the culture under which he or she lives. It is safe to assume that if one lives in a typical western culture and that individual is using a bathroom sink for urinating, he or she is either unfamiliar with social norms, socially inept, or incapable of understanding social norms. If the individual in question actually understands the social norms but decides to continue his/her inappropriate behavior, it may be a matter of rebellion. You may just wish to avoid them.

In other words, if someone knows the rules of society and decides to do that anyway, he/she probably has contempt for other rules of polite society.