If you play Mahjong often, you probably consider it similar to Solitaire. You can play alone and you don't always complete the board (win the game). Because the only competition you have is with yourself in single play Mahjong, it should be a soothing and enjoyable pastime whether you win or not.
In the 1920s, Mahjong became the rage in the United States. It had many different variations of play depending on its origin in China. Each province had variations of the game using the same tiles. This probably is why Americans and other nationalities have developed so many different games with the same name of Mahjong.
When computer versions of Mahjong came out, they had even more varied ways to play. The original game was played with four players, but most internet versions are intended for one player so you can play anytime you have a few free minutes. Play for as long as you like and stop when you need to do something else, but do experience the fun of Mahjong. Careful, though, as it is easy to become hooked!
Each game is different from the last and you have so many different layouts to choose from that you will never tire of playing our latest version of the popular tile game of Mahjong.