Okay, so personal experiences first: Call of Duty takes a special place in my heart.

Usually everyone has his first experience with the first game, but for some reasons, I started with the United Offensive expansion pack. And holy shit it was a thrilling adventure for an eight year old little guy. I remember how hard I sucked at the last american mission, where you had to defend a mansion of some kind.

After the proper assbeating I took from UO, I took on the original game. It was a cakewalk after the expansion pack, but it was as good as the abovementioned one.

After some years (I couldn't play the games as they came out unfortunately) I got my hands on CoD2. The health regeneration system changed the dynamic of the game immersely (instead of rushing through the field in hope for a medikit, you had to stay behind a wall. This slowed down the battle a bit). It's a great game, but not as good as the first and UO for me.

The third part of the series is probably good, I never played it since I didn't have a gaming console at the time.

Then came 2009 (again, I couldn't get my hands on the game right after it came out), and I got CoD4: Modern Warfare. That game made me almost addicted. The singleplayer campaign was an adrenaline-pumping rollercoaster, 10/10 would play it again every time.

But the better part of Moder Warfare was the multiplayer, especially after the 1.6 patch which added Broadcast, the best map of every CoD ever. I got into "competetive" gaming because of it (competetive means really small clans doing HC S&D matches against each other in this case). Since I had a shitty computer, I couldn't continue that experience, but I only have good memories from that era. It was so perfectly balanced, no other FPS games have achieved that kind of balance ever again in my opinion.

World at War was another game I haven't really played, only a few times, but it was a decent game from what I observed.

I bought an X360 in 2010, and the first game I popped in was Modern Warfare 2. The story was immersive as always, and the multiplayer was decent, but not as good as Modern Warfare 1.

The same year, at Christmas, I bought Black Ops. Some say this is the start of the downfall of the series, but I disagree. After Modern Warfare 2, it felt refreshing, at least the single player. The multiplayer segment was almost the same as MW2 had, so it was okay.

Then I had to sell my X360, and I have always owned a shitty computer, so I couldn't play the other games, but from what I've seen, I haven't missed that much.

The best one? Maybe it's because of nostalgia, but I have to say United Offensive. That game made me sad, angry, excited, furious and happy. In like 3 minutes.

The worst is probably Ghosts. I payed with it at a friend of mine, and I was barely able to play through 2 matches. It was almost the same as Modern Warfare 2 for me. And Ghosts was released 4 years after.

The popularity comes from the fact that you don't have to be good at the game. You can just pick it up any time, and given about an hour, you can stand up with having achieved something which makes your mood better. A perfect stress relieve.

Overall, the series has it's flaws, sure, but when I popped in a CD containing a CoD game, I almost never had a bad time.