This is not a game you can be good at. You can suck, but you'd have to try.
I guess that's the whole point of "casual" games, giving the people who play them the perception that they're not sucky at videogames by taking out nearly all requirements for human interaction.
This game relies more on luck than anything even approaching skill. Even the special moves the computer allows, designed to "maximize" your score, fare no better than me randomly shooting somewhere near an orange peg.
Levels aren't randomly generated, but the colors of the pegs ARE random, so even if you master one iteration of it, when you fail, and replay the level you basically have to start from scratch. Imagine playing Sonic the Hedgehog with all the platforms still in the right place, but the badniks have been randomly changed all over the level. Except in Sonic, you could just slow down and complete the level. In Peggle, you simply have to keep playing until luck decides you can progress. Whoo.
This is a game so devoid of the need for a player that it's available to play inside World of Warcraft, a game itself which is farmed out to masses South Koreans because people can't be bothered to even play it, and which requires all the skill of "click here to attack" during the most exciting parts of the game.
Perhaps Yahtzee said it best: [Peggle] is a game for old people and stupids.
So why can't I stop playing it?? I can only imagine it's like that episode of the Monkees where everyone who watches the TV broadcast is immediately hypnotized. There must be something in the game that makes you want to play it, but where normal games satisfy this urge with boobies, this game is more devious, somehow tapping into your optical receptors directly and short-circuiting your brain.