There is a reason for that. Usually people who don't pay that much attention about tennis are the ones who "overrate" Federer's serve. Between quotes as occasionally Federer's serve actually becomes untouchable.
What these people don't get is this: While there are a few very tall big servers out there who basically just hit as hard as they can (and given their size and strength this is effective), the serve, for the rest of the universe, is a very technical and difficult shot to master, specially if you want to explore all its possibilities, like Federer does.
There are at least three different techniques, the flat, the slice and the top spin serve. Federer is very good at them all, but it takes a lot of training and a lot of talent to use all that effectively in the course of one match, specially if you also vary speed an placement. Most players basically chose between an wide or down the middle flat first serve and revert to a generic top spin second serve. Federer always serve close to the lines, varying technique, speed and placement at will. This is EXTREMELY hard and it is the exact opposite of a servebot.
In other words, one thing is to repeat always the same thing, other is vary between countless possibilities.
But to be able to realize that one needs to actually watch the game and not just masturbate at the sight of a particular player.