I myself must join others who are not happy with steam.
First thing that bothers me about the steam is the fact that all games get instaled into the steam client folder. This can be very inconvinient when you are slowly running out of space on that drive and still have plenty of space on other drives.
Also I must say that I dislike the steam client entirely. I hate the fact that steam client needs to runn at the same time as steam games do. I have steam client autostart feature disbled becouse I don't like the fact that it is downloading updates both for games and for itself whenever it pleases as it can consume your whole bandwich. I hate for it to shows me various popup windows even when I least wan't it (when I'm playing non steam based game), which can sometimes lead to undesired consequences (crashing some older non steam games). I cerainly don't like that if you don't have steam client already running and try to start one of the steam games it always goes and checks for updates even if you have them disabled.
I also hate that if for some reason steam client freezes due to some bug you can quickly end up having multiple steam clients running at the same time.

So in short I'm trying to avoid in buying steam games whenever posible.