Two of my oldest and best friends are ILI, and while they can be perfectly friendly, they have told me many times that people whom they think are stupid are stupid (and this includes most of the human race). They don't particularly go out of their way to hide this opinion from those people, either. Low Fe, perhaps.

On the other hand, IEI's may think you are stupid, but they will rarely tell you that directly (higher Fe). Instead, the most you will get is a kind of an oblique comment that calls you out. Basically to put up or shut up.