I played a game until I found bugs that kept me from being able to continue. Only two major ones really stuck out though. One, despite being near the end game, and at the highest tier of research in all four branches, I still couldn't inspect a 1 curiosity quest item on a planet I owned. A minor issue, so I just ignored it and kept playing.

What really stopped me, was when I encountered the Lumeris, and after setting up a peace treaty and trade agreement, I was bombarded with insults from them. Every 5-10 seconds a new diplomatic message appeared. Through saves and everything else I could try, no matter what they'd simply resume sending me the same message over and over again.