Did you ever try cheating a little every day, as opposed to once a week? I have to admit, some of the foods I eat every day which I find essential to my muscle building (or getting lean) feel like cheat foods. Greek yogurt mixed with protein powder and a banana is one of those things. 40 grams of protein and tastes so damn good.
I don't think being extreme one end of the spectrum or the other is good in the long run. In my opinion it won't do anything for long term adherence -- which is probably the most important component for a successful leaning or muscle diet. My philosophy is to find the middle ground between lazy and gung ho, and cruise right there, with dips and peaks. Most days are status quo and sometimes you're going to have pizza and ice cream -- but others you will come in at your calorie/macro goal perfectly.
Trying to be perfect all the time and then rewarding yourself in one moment could lead to overeating. I could say this is all my opinion, but I have my own empirical evidence on the subject. I'm also diet coaching a guy who couldn't get on track on until he ditched the all or nothing mentality and went for the "cruise in the middle" thing I was just talking about.
I don't want to sound super conservative about an approach to building "lean muscle" as you say, because there's hard work and good dieting involved. But being extreme may help you pack on some fuscle instead of muscle.