Now this is my own opinion, its perfectly fine to like these games however I believe them to be incredibly overrated and I'm probably going to get hate for this take because there is more than one sacred cow on this list.
1. The Grand Theft Auto Series
I'm going to be honest. This game has no reason to exist anymore. It used to be that it was the only mainstream game where you could just go out and wreck havoc in the middle of a city. Now not so much. There is an entire Genre of wide open sandbox games for you to play and some of them are MUCH better. I remember playing GTA IV and I gotta say, The game wasn't fun. The gunplay was extremely repetitive the driving was boring. It just wasn't fun. Now with games like the Just Cause series and such. The whole, do aynthing kill anyone style is no longer exclusive to GTA and it seems like everything it does has been done better in a different game.
2. The Call of Duty series
Seriously these games just aren't that good. They aren't particularly well written, the gunplay is repitative and there is basically no difference other than appreance between most of the guns. Then you have the fact that they release one every year and there is nearly no changes. It's like a sixty dollar map pack. Fuck COD
3. Assassins Creed
I know people love these games but to be honest the first one I actually found a moment of fun in was Black Flag. The first one I would actually call a decent game would be the most recent one Syndicate. The early games in particular are just atrocious. The Combat is boring as fuck. The stealth system is just awful. I mean, hide in plain sight sounds awesome but when you are a dude armed to the teeth wearing a robe you shouldn't be able to blend in with a group of commoners. The plot has far to much badly done science fiction. Then you have the fact that the Series replaced the Actually Awesome Prince of Persia series. So I think the Assassins creed games are overrated.
Now don't get me wrong, I actually enjoyed the pokemon games I've played. They are actually good games. However that does not mean they are not overrated. The fact is that the each game is essentially the same. Its not some great innovator, its just a Good J-RPG yet I know people who talk about them like they solved world hunger and for that reason I sadly have to list them, which is sad because my first video game was Pokemon Gold
5. The Madden Series
Now this series hasn't changed in years. I know people who pre-order them and get them that day but to be honest this series changes even less than pokemon and call of duty. Which means that a game that is even more the same than the others gets released every year. Honestly you've play one you've played them all.