Im an enfp and looking back before i knew anything about socionics the istp's i knew i pretty much jived with them. I think they like talkative outgoing people. I pretty much clicked with them real well. I think culture and upbringing plays a big factor in which an istp would be a withdrawn suspicious person or someone who doesn't fit that stereotype.Actually many i known were plenty outgoing , humorous, and more talkative then me.I known some that were sorta quiet . One in particular i grew up with was a younger brother of a friend of mine( just 1 year younger the me and his brother). So i was like kinda fond of him so me and my friends like kinda took him under our wings. I noticed they tend to be more outgoing when in the company of combination esfp's-enfp's. In their company they sorta resemble their mirror, the ESTJ.