One thing I have learned over the years is that repetition causes boredom. This is really true for all things in life, but especially true for video games since so much of gameplay is repetition to get better. No matter how good a game is, if I play it enough I will definitely get bored. Good games will last longer than bad games before boredom sets in, but it still inevitably happens.
In the past I would get these “gaming blues” and think maybe I was outgrowing games. Sometimes I would even fall into a light depression wondering what I would do with my free time without games. Nothing I tried was as fun as games, but games were not providing that fun anymore either. Over time, however, I noticed my interest always came back with time. Maybe just a day without games was enough, but sometimes it even took a few months.
I am finding this happens less and less as I get older. As a kid I probably played games too much. I would get a new game and beat it within a few days. Since my allowance only afforded me a new game every two to three months, I had to endure a lot more repetitive gameplay.
I do not play games as many hours these days compared to when I was a kid. Before adulthood, I probably played at least 40 hours a week. After adulthood, it is more like 20 hours a week. I also do not play exclusively with that free time. I now post on forums and write blog posts about the games I am playing, so my overall playing time is probably closer to 10-15 hours per week.
Besides playing less I have learned that playing a variety of games instead of just one reduces the chance that I get will get bored. Before I might play one game exclusively for weeks and months until I had done everything, but now I usually play a different game each day or every few days.
I seem to stay interested as long as the games are in different genres (RTS vs RPG) with different playstyles (casual vs hardcore). One day might be Civilization 5 for hardcore turn-based strategy. The next day might be Skyrim for casual role-playing. Another day might be League of Legends for hardcore arena PvP. Finally, the weekend might be World of Warcraft for casual dungeons with friends.
The important thing is that I will get bored of games sometimes. It is not that the games are bad or my interests have changed. I just need some time away from games. I think an important part of life is understanding your feelings. You can then logically decide whether a feeling has merit or unfounded. If it has merit you might make a few changes to your life, but if it is unfounded you can simply cast that feeling aside.