An unofficial, very unreliable and seemingly paranoid source advised me that if I go to Pakistan then my subsequent international immigration procedures will become complicated due to security concerns.

Would a visit to Karachi, Pakistan -- in the context of a year with a RTW (AONE4) ticket along with several international trips aside from and included in the AONE4 (Bangladesh, Nepal, India, Hong Kong, UAE, S. Korea, England, S. Africa, Poland, Italy, etc) -- set some sort of flag in the immigration database that could make my subsequent int'l travel less smooth?

I'd really like to go visit a friend in Karachi, but don't want to create immigration problems for myself. I am a US citizen. I have quit my job to do this travel. (Might not being employed be another possibility for alert???)