He had Lilly's eyes. Every time Snape looked at him he was reminded of his betrayal and loss.
But also a reminder of love, and probably the only happy moments in his life. One of the things I’ve learned recently is that hate fades faster than love. Been helping to create my 20th high school re-union and I’ve found that the classmates I was fond of then I’m still fond of now, and the classmates whose names I couldn’t even say then without cursing I actually kind of like now.