Believe me when I say all of the WOG retcons made it worse...much worse. I can't remember the details, but Future just made it even worse. It's revealed that Greg came from a super strict background and had a very unhappy childhood (music wasn't allowed in his house), so when he finally gets free of all that as an adult, he wants his own children to be much happier and more free (Greg also sends them a bunch of letters, which they never opened). This makes Steven mad because he'd never had the chance to do normal kid stuff like go to school or to the doctors (made worse by Steven going to the doctors at least once in the show IIRC, and going to school in the secondary canon comics), and he crashes the car and then deletes Greg as a contact on his phone. No I'm not making any of this up.