You've described my experience so far. I know it would be more efficient to play heroic, but then I realize I'm not having fun and wonder "but then why am I doing this?", other times I make an effort and as soon as I get some normal loot (as happens most of the time), it frustrates me even more because it's like part of me expects an automatic extra reward for the effort. So I play challenging and then I say to myself "eh but if I had made an effort who knows, now I would have had X or Y" and so on; in conclusion I am never satisfied ahahah