Expect you don't because people do not fit into classes, especially not classes that simple (i.e. only 4).

It means you will behave annoying, toxic or otherwise unpleasant to people because you expect them to have traits/personalities they might _just don't have_.

In my experience any classification I know of is more hurtful for society then it's helpful and should be avoided.

Also in my experience they are quite often used in a slightly degradating way by people outside of that group which either don't understand or like that group or just want to make themself feel better by lifting themself over other people.