Started as a mostly normal back and shoulder workout, but when I did the standing barbell rows, my right shoulder told me "STOP! Right Now!". I put the bar down and vetoed doing any more, this wasn't just muscle fatigue, this was something that if I did more of would injure me.
So as a replacement, I got a new exercise. Standing dumbbell lat raises. I stand upright with a dumbbell in each hand. With my elbows straight, in a controlled movement (no shruging or throwing the weight) raise my arms until I am in a T shape, then lower (not drop!) my arms back to my sides. These didn't hurt, but they did discover even more brand new muscles in my shoulders that have been "coasting" the last 5 months.
I did such a good job on them, that I burned out my shoulders. On the machine shoulder press, instead of doing 3 sets of 15, I could only do 10, 8, and 2, while lowering the resistance several times. By the end, it was a noticeable effort to just raise my arms over my head. Yow.
Another new exercise as well. I forget it's name. I squat down, throwing my ass back and my chest forward, balanced on my feet. Holding a barbell in each hand, I pull them straight up from the arms down position up to my sides, pulling with my back. These left me lightheaded and covered with sweat.
Noticed something interesting as I was getting dressed in the locker room afterward. There is a phenomonon called "pump". When doing resistance work, the muscles will swell and fill with blood, making them look bigger than they really are, even tho they are actually much weaker in that condition. I've now lost enough surface fat, and gained enough muscle mass, that I can see the pump in the mirror. It fades away after only a few hours, but it was fun to see.
Stronger and stronger, bigger and bigger.