I realized that I was looking at pictures and being jealous of other people in the best moments of their lives. Even though it's a combined highlight reel of everybody you know, it feels like everyone is always enjoying their life.

If each of your 500 "friends" goes on a nice vacation once a year, you're going to end up with 1-2 sets of photos every day from a "friend" in some exotic location having fun. Even though that might be the only fun thing any of them did all year, it feels like everyone is going on vacation every day.

If each of your 500 "friends" is in a romantic relationship, you're going to end up with a happy photo or status update from a "friend" telling you how great his relationship is. Even if his relationship only has 1 happy moment in the year, it feels like everyone has a happy relationship.

No real human being on the planet can measure up to this, and people end up being disappointed constantly.