Tip for avoiding therapy-speak:

You gotta let the characters screw up and say/do the wrong thing from time to time. It's one of the top ten things I absolutely hate most in my writing, but healing isn't linear and everyone screws up from time to time, so, much as I don't want to, it's necessary to keep the dumbass stick around for the times they would legit get hit by it. Then use those dumbass moments as opportunities for further growth and character development once the in-universe tempers have cooled.

Tip for avoiding contrived bullshit:

Figure out what each character's main stumbling blocks are, and make sure to put those under their feet when you need them to mess up. However, also rough out how many times they'd logically stumble over these issues in a seriously detrimental manner before they start learning to try and avoid these stumbling blocks. Then figure out what new stumbling blocks they'd run into while trying to avoid the old ones. Watching someone trip over the same step repeatedly gets boring after awhile, so stack a bunch of steps together to form a flight of stairs and push your characters down them!