Racing game multiplayer (Steer out)

I spent about a year on this one.
At first I was just tinkering with vehicle physics (mostly suspension). Then it turned out I quite enjoyed making 3d models for this game and I was hooked. I also added multiplayer, but later removed it to focus more on the game without worrying about online stuff.
After a year I realised that it was absolute not fun to play and the AI was also weird so I just moved on.