I have great difficulty maintaining eye contact, which unfortunately conveys false impressions of either shiftiness or submissiveness. I found it extremely useful when someone pointed out to me that a)even for people like me, it is not particularly difficult to keep one's eyes on another person's forehead, and b)at the typical conversational distance (at least in anglophone countries), it is not possible to reliably distinguish when someone is looking at your forehead from when they are looking you in the eyes.

Corollary: Because looking at the forehead is easy, I now have to consciously remember to look away occasionally, since maintaining the false appearance of eye contact much more than 65% of the time (again, in anglophone cultures*) will seem just as creepy to your interlocutors as actually doing it.

*I don't recall where I original saw the statistics for eye contact, but I'm fairly certain that it was typically about 65% of the time during conversation in the US and UK, about 10% of the time during conversation in Japan, and 80% of the time during conversation in many Arab countries. I recall the US Transportation Security Administration coming in for some mockery post-September 11th for making avoidance of eye contact a factor in behavioral profiling, given that putative terrorists would be likely coming from countries with a higher norm for eye contact than in the US.