Most people tend to react positively to INTPs, though INTPs may find that some may be
nervous around them. The ability of INTPs to process data very efficiently, along with
the ability to go unnoticed in groups (allowing them to hear things that others may not
want them to), gives them the ability to come up with conclusions that others may rather they didn't arrive at. The trademark "stone face" they possess along with the lower
level of body language makes it difficult for others to figure the INTP out. This can
be useful, but it can also put some people off, who also may be put off by the
tendency of INTPs to split hairs and play with words. The INTP constantly gathering
any information that he comes across (and retaining for long periods of time) doesn't
help matters much, either.
INTPs tend to be remembered by everyone, though they may not be noticed at any one time.
That leads to everyone knowing who they are, but not necessarily paying attention to
them. The INTP may feel neglected and ignored.