Thats a tough question. I usually wait a few months after release and see how it turned out. Unless its a game developed by Bethesda or CD Projekt Red. I lost some faith in Bungie with them giving away Destiny to Activision.
But the worst game i have ever bought would have to be Kingdom Underfire for the Xbox. I couldn't get very far in that game.
You don't know shit until you've played Ride to Hell Retribution seriously it's so bad I think everyone should buy it. That and CoD ghosts I really regret buying it was shit
It's funny to see those who say destiny still play the game. If it's that bad then simply quit playing it. Saying it's an addiction is a lame ass excuse. Just shows since people are ignorant hypocrites.