Yeah, that's very true; I'm not claiming that rational thought is useless for social interaction, it is good to sometimes stop and think about your social interactions on your own when you have some downtime.

That being said, there are downsides as well. If you're using rational thought instead of the social parts of your brain to decide how to react to social situations, you will tend to react differently. Not that you're wrong, or irrational, but you just won't respond to social cues in the way people expect, and that itself might give you a disadvantage.

Thinking about this, it is actually reminding me of the behavior of a friend of mine who has a form of high-functioning autism; she's very smart, but she reacts quite differently in social situations then most people would expect. Perhaps that is basically what she is doing.