Andrew Sullivan has a provocative quote from a Dutch sociologist:
Are women more attracted to the life of a desperado than men?" asks sociologist Jolande Withuis in her essay "Suffer, fight, become holy" on radical women Muslims. She sees their motivation in the promise of complete devotion. "Faith offers radical women Muslims a 'total' identity that isn't limited to certain occasions and which is considerably more serious than anything else. It demands effort and renunciation, yet offers fulfillment and peace of mind. Boring or tiresome rules, such as covering oneself or not being allowed to eat certain foods, become a source of self-awareness. They are like anorexics, who derive satisfaction in overcoming hunger, even if it is harmful to their health. Correspondingly, these women occupy themselves to the point of absurdity in trying to determine whether things are 'haram' or 'halal' – and this occupies their time and gives them the pleasant feeling of pursuing a meaningful life.
I'm not that interested right now in the question this essay asks, but the part I've bolded jumped out at me. We current and former Orthodox Jews know many who seem obsessed with the following the letter of the law to an absurd degree. And even that's not enough for them -- they accept more and more stringencies upon themselves, going far above and beyond what is required by halakha. Why do they do this? What do they get out of it?
Ask them and they'll tell you that they are merely fulfilling God's commands or, if they are the more spiritual type, that paying close attention to the intricate details of halakha infuses every aspect of their life with meaning. I think that's probably a fair assessment, leaving aside the people with actual OCD.
In discussing why people become or remain religious, meaning generally comes in at the top of the list or in second, after community. I didn't fully realize until I read the above quote that meaning comes in two forms -- one, the overarching sense that the universe makes sense and that we are here for a reason, and two, that the feeling that every action we do can be meaningful.
When I tie my shoes, it has no real meaning, but when an Orthodox Jew of a certain mindset does it, following carefully the halakha which states you must put on the right shoe before the left, then tie the left before the right, it becomes a way to connect to a deeper purpose. Some people apparently find this very satisfying.
Is this a healthy way of living? Who am I to say? I'm pretty sure I don't have the personality type to find such absurd rules meaningful even if I did believe in God. ("Does God really care how I tie my shoes?" I asked as a kid when I first learned that rule.) The analogy to anorexia made by the author of the above quotes strikes me as unfair in the sense that anorexia is objectively dangerous and unhealthy, while I haven't seen any evidence that adherence to halakha is particularly bad for you. However, the idea that the obsessively halakhic Jew (or strict Muslim, etc.) is deriving psychological satisfaction from his actions and omissions is an interesting one albeit a bit obvious in hindsight.