Should we forgive our enemies? Why/why not?

I mean, Twilight Sparkle and co are a very forgiving group. Nightmare Moon, Discord, Trixie, Gilda, Diamond Tiara, Changelings (sans Chrysalis), Sunset Shimmer, Juniper Montage, Wallflower, were all villains/rude, who are good now. So if you want to take away a lesson from My Little Pony, the answer is yes. Although your results may vary.