Equal to Mahjong and Solitaire
That is one of the reasons that the versions for the Gameboys are among the best. There is something about a puzzle game that you can take with you that makes it appeal so much more than one you have to boot up or load. The graphics of Tetris are very simple and there aren't "levels," only the same game getting faster and faster.
There are few games that I ever play after 8 years, but Tetris DX is the only one I have played FOR 8 years. I play until I "die" before I go to bed almost every night. The DX version Tetris is one of the best because it isn't weighed down by all the other modes of play that have been invented for games like Tetris Worlds.
If you have a GBA, a GBC or a GB, Tetris DX is a game that should be in your collection.