Friday? I don't think it's the worst song ever. It's not "good," per se, but I get a weird enjoyment out of listening to it. I'd ALMOST put it in the outsider music category of like Shooby Taylor or The Shaggs, but I don't think it quite belongs there. I dunno, it's definitely a musical oddity and it's burned itself into the public consciousness.
It also drives my co-workers nuts, which I enjoy greatly.