My problems were:
Massive build ups too quickly: Build an army too fast then have to paint it just makes too much stress. Fluff is great but when the fluff requires a massive army from the get go, again the stress goes up. Skaven, Imperial Guard, Warriors of Chaos, High Elves and FoW are all victims of this.
Building up an army based around a single unit or tactic: Put simply, over focused on one thing. I may like a specific unit for what ever reason but if I don't like the rest, then it's just a stress to paint up. Likewise building up based off of one tactic means that the army get boring once I have that tactic down. Dark Elves, Tyranids, Minotaurs and Wood Elves are all examples of this.
Not fully thought through: Certain units and armies really grab my attention but I don7t think through things like paint schemes and what not. So I get the models, want them to look nice and have a massive brain fart on how to go about it, Skaven, Retribution and Circle all show signs of this.
So in order to return to my roots in the hobby, I've realized that I needed to take a huge step back and in some ways wipe the slate clean. I'm not talking about a complete reboot, sell everything off, but more of a mental wipe, get ride of the clutter in my mind. This in turn brought peace to armies that I have struggled with such as the guard.
First, all painting projects have been taken off. Large armies will just be fielded as is so that I can play some games, but trying to build them up or paint them have been removed. Should I feel like doing a major project, then I have some ready to go.
Second, start small. Build the army from the ground up with fluff added in as I go and complete each before adding to the army. Also, keep several small projects from different games going at once so I can change out if I feel fatigued.
Third, have fun with it. I've never built a list solely for the purpose of winning a game, now I'm just going to build on whim and go back to using what I got and improvising, adapting and overcoming.
So how does this translate over?
Battletech is freshly started so no change there.
40k, I've got some Nurgle demons to work on (oh those lovely adorable cute nurglings
Warmachine: Khador is coming along smoothly and it was the first model I picked up to paint. Others again, I'll just see if I get a paint scheme idea made or not once I finish with the few khador models I have left to paint.
FoW: Going to focus on the tanks then expand into the infantry in some order.
Fantasy: Skaven go per 2 so I have no army now to speak of that I am building
Last, I want to build a chess set! I have always wanted to do so, now I am going to make it so.