What do iTunes star ratings mean to you?

Rating things on a five-point scale is never easy, yet it's a system convenient enough that film critics, wine connoisseurs, and Rolling Stones all over the world use it. Here's what I mean when I rate songs in iTunes (this also applies to rating photos in iPhoto and similar systems):

[no rating]    I never got around to rating this song, or I haven't made up my mind yet. This should be looked into.

There is something wrong with this song. It's terrible, or the file is broken, or the tags are wrong, or it's some 45-minute experimental piece. In any case, I don't want it to shuffle on or show up in my playlists and I should look into why it's in my library at all.

This is a bearable song. I don't hate it; if it comes on, I'll likely skip it, but it's basically earned its stay in my music library.

This is a good song. I want to hear it here and there even if it's not exactly a favorite.

This song is sweet. I want to hear it frequently and it's very unlikely that I'll skip it or remove it. (Note: songs often flip between three and four stars)

This is a classic. It's either a masterpiece or a track very dear to me. I want to hear it, but careful with it - it may play too often. This should be used sparingly.