I play a lot of computer games (too many?). One thing I like to see in a game is a sign that the game designers enjoyed themselves when making it. Jokes, meta-comments, amusing little subtleties all contribute to the atmosphere of a game. They probably also contribute to the quality. I figure a team that's comfortable enough and creative enough to put little tidbits like that into a game is in a situation where they will design a better product.
For example, Might and Magic VI has a setting typical of fantasy games. Throughout the game, however, the player explores ancient ruins and environments that show highly advanced technology. One temple requires the player to collect words of power from long-dead inhabitants of the temple: the captain, first mate, navigator, communicator, engineer, and doctor. It turns out these are all the names of Star Trek characters spelled backwards. In another part of the game, the player meets a character shunned by the rest of her village because her cat smells very bad.
Right now, I'm playing World of Warcraft (yes, I'm an unimaginably huge geek). A few Sundays ago, on Easter, I kept running across brightly colored objects. What they are should be pretty obvious: