You can absolutely make your game and you should. If you have any interest in being in the game industry it's critical, and there's no excuse anymore for not making your own game, there's basically two ways of doing it. You can either get a game creation tool, of which there are many. Use your favorite search engine and search on "make a game," and you will find tons. Things like Game Maker Pro and that kind of thing. All the way up to the professionals or unreal editor and that kind of thing you can make your own game. There are student versions of many of theses more expensive games that reduce the cost for people who are, in college or in universities. And then there are Mods, a lot of your favorite games ship with the tools to make new versions of the game or, add on's to the game. And some of those are so extensive that they don't even resemble the original games. So, if you have a favorite game, go out there and see if there's a tool for it and start changing it.