"Different things work for different people."

Living life, getting through the day, is obviously an enormously complex process. Whether we are rational or irrational, we make decisions based on a large number of short-cuts. These "short-cuts" have evolved over time and have their origins in our routines, our values, etc. However, since they don't completely capture our full decision-making system (i.e., don't reproduce every time the decision we'd make if we had enormous time and energy to decide each one), they introduce certain inefficiencies (or even inconsistencies).

I think that a lot of advice represents "hacks" for getting around certain built-in inefficiencies. It would be enormously trouble-some (and arguably counter-productive) to rewrite your whole meta-code, but a patch is worth adding, if it works.

Thus I think the reason advice works for some and not for others is because it is a patch for a particular (hopefully common) form of inefficiency, but the patch only works if you have that efficiency or if the source of the inefficiency is the same.

I had a friend in graduate school that had a mental breakdown and lost most of her short-cuts. It was a really amazing thing to watch her make decisions from ground zero. I think she appreciated the experience because, to a large extent, she had the opportunity to pick and choose which new short-cuts to assimilate. As an intelligent adult that was more or less X-rational as well, she proceeded in a very systematic way. The result was a very efficient but somewhat strange decision making process.