I'm not having a problem with falling into a rut or anything, but re-training myself what intense is. I've only "been back at it" for a few months after years of layoff. I'm re-learning how to push past my comfort zone. For example today during straight bar curls my forearms and biceps where screaming but I could do another rep. Previously I would have ended the set but today I got the other rep and then went for a half rep just to see if I could handle it. Maybe next week that half rep will turn into a full rep, etc.

Etc.