I'm lucky then, because I liked the side missions...except the fake injury ones, those are lame. I do agree with you that it's stupid that you HAVE to do them to advance in the game, but really you don't have to do a whole lot of them or anything so it's not THAT big of a deal. I pretty much just did the Mayhem, Drug Deal and Escort missions.
Another plus is that when you fail a mission, you have the option to restart it, rather than end up at a hospital and have to work your way back over to the mission starting point.