Kinda. Completion percent is definitely a factor. Part of it is I am sick of all the extra fluf on my card, it looks terrible to me now in hindsight. Japanese console, phone, ios, windows 8... all that crap. It doesn't feel like my tag, it feel like the product of obsession and not love for the games I like. Losing my computer was my breaking point... because I bought it that particular computer because of achievements and now its gone.
I think Prove your Worth is the one with all the groups of uruks and you had to help him survive. That ones the easiest imo. All the other ones get fucking ridiculous with how many uruks they throw at your poor captain.
I didn't experience any rage today but the knife mission I did could've easily lead to sweating and raging. I had to sneak to an execution site, brand all seven archers, and then kill the whole Uruk patrol WITHOUT BEING SEEN. I did it on the first try but it could've gone worse.
And oh my god I would've lost my shit if that happened to me.
It wasn't all for nothing as he died after the recruitment mission (I was hoping for a prove your worth mission as those are much easier) but all his recruits died along with him (that happened because I ran away to take out a captain that I issued a death threat because of course the power struggle managed to bring him and three bodyguards there) so I did get the "No Power in Numbers" achievement.
I think what makes the stealth missions so frustrating is the fact hat there's no immediate replay as there's NO checkpoints. Who thought that was a good idea? "Hey, let's have them go to jump over a group of obstacles to get across some uruks but then have him fall in the middle of them to make him abandon the mission and run back to the mission start point." -_-