It really depends what foo is. I don't think it's rational to waste time on unimportant things. If foo is eating red meat, then I don't think it's rational to really worry about it one way or another.
I think part of the problem is that most people are conditioned into many beliefs from a young age
I think it's irrational to not consider new information when processed. So, again, this depends on what foo is. If it is obeying speed limits even when no one else is on the road, and your friend learns the penalties for not obeying road signs when they get their license, they would probably find it irrational to not do the speed limit, even if they hate it. They wouldn't want to risk the fines, license suspension, etc.
However, let's say your friend's brother has stronger beliefs and can afford any fines and legal action. He could think about it and still decide that it's rational to not obey the speed limit. This doesn't make it right; I think right and rational are mutually exclusive.
When I mention conditioning, I mean from a very young age.
For example: Throw salt over your shoulder if you spill some -or- Green skinned people are bad and you should never trust them or allow them in your neighborhood.
Now the former is pretty harmless but not so the latter. In both cases the only explanation is "that's how I was raised" which I don't find compelling or rational.
If the person has some stronger belief (e.g. people are important, and hurting them unnecessarily is bad) that can override “never allow green-skinned people in your neighbourhood”, they're redeemable. If they don't, they're evil. (Evil people can be rational, too.)
I think part of the problem is that most people are conditioned into many beliefs from a young age
I think it's irrational to not consider new information when processed. So, again, this depends on what foo is. If it is obeying speed limits even when no one else is on the road, and your friend learns the penalties for not obeying road signs when they get their license, they would probably find it irrational to not do the speed limit, even if they hate it. They wouldn't want to risk the fines, license suspension, etc.
However, let's say your friend's brother has stronger beliefs and can afford any fines and legal action. He could think about it and still decide that it's rational to not obey the speed limit. This doesn't make it right; I think right and rational are mutually exclusive.