Discord wasn’t really a bad guy, if anything more like a prankster. He is the embodiment of chaos. He wasn’t a after the throne, he just wanted to screw with ponies by literally fliping everything around. Discord never had friends and such never had to take that into acount of his actions. Seeing Fluttershy turn away from him after breaking his promess of not causing a colamety finally made him see his actions do have a price, and he didn’t want to lose the one friend he’s ever had. This is my thought anyways.