I just had a nasty little revelation about Snape and Neville. No, not like that.
It just finally clicked for me why Snape was always such an unspeakable ass to Neville.
Because it could have all been so different. Neville was also born at the end of July, and his parents were in the Order. If Voldemort had decided to go after the Longbottoms instead of the Potters, Lily would still be alive and Snape wouldn't be stuck in a job he hated, sworn to protect a child he hated, and who knows? Maybe there still could have been a happily ever after in there somewhere.
Except --
Snape wasn't that stupid, either. He also would have realized that if Voldemort had decided that Baby Longbottom was the kid who had to die, Snape wouldn't have been all panicked about Alice's safety. He certainly wouldn't have defected over it. The Longbottoms, more likely than not, would have been caught off guard and Voldemort wouldn't have offered to spare anyone. They'd have all died and Voldemort would have most likely won the first war. And while Snape never did reach any great heights of wisdom and maturity, at that point in his life he would have at least realized that muggleborn Lily wouldn't have a place in Voldemort's new world order.
Poor Neville: A reminder of all the worst parts of Snape's life wrapped up in one easily intimidated package. Luckily, Neville turned out to be stronger than Snape bargained for, and definitely more mature than Snape ever managed to be.