There are Two types of people - humour

"You say there are two types of people?" "Yes, those who separate people into two groups and those that don't."

"Wrong. There are three groups: Those who separate people into three groups. Those who don't separate people into groups. Those who can't decide."

"Wait a minute, what about people who separate people into two groups?"

"Oh. Okay, then there are four groups."

"Aren't you then separating people into four groups?"

"Yeah."

"So then there's a fifth group, right?"

"You know, the problem is these idiots who can't make up their minds."