The blithe self-denial is as prominent in this personality as the selective quality-seeking. It is most understandable for someone to have a great appreciation for hard bop, but it's not easy to see the benefit of rejecting all other music, not with disdain - just indifference. When the same attitude is there towards one after another of the kinds of things that make life enjoyable, that's a personality type.

I don't think English has a word close in meaning to this peculiarity of character. What would be a summary delineation of it in a few words?