Portishead is mellow, depressing, sometimes creepy, and always awesome. I heard their song Sour Times on the radio quite a few years ago and it was catchy. When I say catchy I mean it makes you think of killing yourself yet is still enjoyable. There's nothing better at boosting morale than singing "nobody loves me" over and over in the saddest voice possible, but that is why Portishead is awesome. All of the songs have emotion and feeling behind them that you can feel in the singing and words. Their song All Mine from their 2nd album is one of my favorites. It starts out being happy and in love (though still depressing) and devolves into creepy stalker mode towards the end, yet keeps a level of class that makes you want to feel the same way about someone.