Since others have already given plenty of reasons for the hate it receives, I'll just add my own experience to amuse myself.
The only thing I've used Origin for is Mass Effect 3 (Digital Deluxe Edition on Amazon for $20, booyah). I have had zero problems with it. Other than the minor annoyance of it telling me ME3 is not prepare to be launched because it hasn't finished downloading the soundtrack. When I finish ME3, I will install the extended ending, then play/watch that, then uninstall Origin and never have plans to use it again. Side note: After playing through some of ME3, I think it was pretty low to rip the Prothean out of the game to sell as extra (luckily, I essentially either got it for free or bought it and only paid $10 for the main game ^^).
OFF TOPIC NONSENSE:
I'd rather only use Steam or play games independent of Steam and any other digital store client. I will still continue to purchase from whichever service gives me the best deal (unless it'd be tied to their client, like Capsule, Gamefly's thing, Gamestop's thing, Desura etc.).
In my experience, likely due to joining Origin after a year of bug fixing and minimal time using it, Steam has far more problems than Origin. Steam freaks out and freezes if you try to use it too quickly after exiting a game or sometimes by just switching focus to it from another basic desktop program (the latter being much more rare). Sometimes if you quickly switch to Steam and double click a game too rapidly, Steam will launch some other game that wasn't anywhere near your cursor (e.g. I try to launch Awesomenauts, and it somehow launches STALKER, which was at the opposite end of the screen). If your bandwidth is low (i.e. you're saturating your pipes with download/s) Steam, instead of just being slower like most every other website, sometimes refuses to work at all. The store almost always works fine when your bandwidth is scarce, but the Community features and trying to launch a game often fails (because it needs more than a few KB/s to authenticate your game, I guess, somehow...). Its download manager doesn't have a queue system and is slow to respond. Turning off the "Download Updates for the this game automatically" feature never actually works. So often, I'll start lagging horrendously in a online non-Steam (and sometimes even while playing Steam games) game because of Steam downloading updates I told it not to. In addition, even when you do "pause" a Steam download, it takes another 10-15 seconds for it to actually stop. So you continue to lag in your game after alt-tabbing back in.
I still really like Steam though. I have an unhealthy affection for its community features. I think it needs to be reiterated more often on the internet that it's possible to criticize something you like. Maybe if that's made clear often enough, someday more people will grasp this concept.
I'm really bitter in my posts sometimes, I need to find some perspective. Or take one of those "chill pills" I've heard so much about.