Winter!: Prepare for holiday gaming!
At work, we have this machine called Megatouch. It's full of simple little mini-games just like this, but it costs 50 cents a play. This game saved me a lot of money! =D
Work Time Fun is a great way to waste time. The game is full of varied and interesting graphics. Mostly, I think the attraction of the game is the underlying Japanese culture. It's an absurd version of the culture, but it still has its basis on the real-life experience of the average part-time Japanese worker. (In Japanese, it's called "Part-time Job Hell".) The simplicity of the game means anyone can pick it up, and the variety of games means that everyone will probably find a game that they like to waste their time playing. After a while though, if you're playing for titles in the game, you'll find that some of them are difficult to achieve without wanting to throw your PSP against a wall.
Game Traits applied to WTF: Work Time Fun (PSP) by Skyskid