If you think about it, we treat cars in most GTA games as disposable lol. You can always look for a new one. In GTA: Online if you buy a car it's insured so you can have it back in case it gets blown up, and if another player blew it up they'll pay for it when you reclaim it on Mors Insurance. I guess that's what makes it fun wrecking them in the game, you can always have another one.