People seem to think that introverts are unfriendly or aloof - don't they KNOW that some people are choosy about who they talk to and what they talk about?
If someone says that they are "choosy" about who they talk to -- I can see where that could be deemed as unfriendly. It says that only certain people meet my criteria about who is/isn't worth my time, which would seem to me to be a classic illustration of the condition of being aloof (for some reason the example of Maj. Charles Emerson Winchester on MASH comes to mind). It's hard to seem friendly when acting this way. IMHO.