Several times my settlers simply left every job they have been assigned to and kept standing around= happiness started to decrease again. At first i kept assigning every single settler back to his job but i gave up after a while.
What was also very annoying when you have a long gameplay time(bloated savegame i guess) there seems to be a delay. For example i press the button on a settler look at one of my stores, press the button again and then it takes 3-4 minutes till the message shows up to confirm he started his business.
After the 2nd time i simply reloaded a save game...
The rest is just sitting around, listening to music, wait till you gain 1-2%, run to a bed and sleep for 24-48 hours and repeat. Plus you cant really take a break since everytime you leave the settlement the happiness drops down to 80% again.
I do enjoy fallout and bethesda games in general but seriously guys this trophy was a pain in the a$$.
For future games/DLCs please make sure trophys are achieved by plaing. This one was simply a waiting game. A few hours watching the screen with nothing happening. If settlements would function 100% right it, maybe it wouldnt be that bad. But the the way it is with all the bugs and missing features its a very bad gaming experience getting that trophy.
Just received platinum, im ready for the DLC but please no other trophy like that one.