I'm starting this thread to list some of the errors that I think are frequently made while trying to type people. Please feel free to comment on my observations or add your own.
1: Sensors mistaken for intuitives, because the typer feels that sensors aren't that bright.
2: Feelers mistaken for thinkers because the typer thinks that Feelers aren't as bright as thinkers.
3: Thinkers typed as feelers, because they allow their emotions to get the better of them.
4: IPs mistaken for IJs because they form opinions rapidly.
5: IJs mistaken for IPs because they take their time deciding what they are going to do.