I think it is based upon the total number of achievements you have.
According to the forums, 90% of players hate achievements... however, in game, of players actually... playing... 90% seem to appreciate them =)
Everyone cries about jumping a jeep... have you even tried it? It's not like it's a gimme... and the best part is, it's very easy to avoid if you detest it so much.
Kill a perk ride, get a pilot hit, down X enemies in one run... all good things.