I remember playing Wolfenstein 3D for about an hour, then getting bored with the repetitiveness and lack of identification with the protagonist, and never touching the game again.
When Doom came out, I tried it for 10 minutes, concluded it's W3D with better graphics and aliens instead of Nazis, and never touched it again.
Of course I don't mind that others enjoyed the game. Unfortunately these games became so popular that everything turned to first-person 3D and killed most of the genres I had enjoyed, and so I eventually stopped playing completely.