you will focus on things you think are supposed to affect happiness

I think it would be more productive to focus on activities that are different from what one is already doing. If my non-akratic roomie and I are both doing activity A, then even if activity A is helping my roomie, it won't help me - it's already failing at the task. Things that my roomie does that I don't, whether they seem intuitively likely to affect happiness or not, would be the targets of investigation.