Well, this is a great example that just happened today for me.

At my grandma's house, my aunt got me a copy of season one of the Telltale Sam and Max games (fun fact: it's a European copy, and I'm American, but I've had no problems so far with it regarding compatibility or reigon restrictions, or anything of that matter. The autorun decided to break on me though) I came home a few hours ago and installed it on my dad's computer, planning on transferring it upstairs to this computer I'm on at the moment, since this computer's DVD drive has gave up on me. It took ages to transfer all of the games on a USB that only has less than a GB of space, and I finally got it done a good moment ago. I clicked on that first episode, and I got an error telling me to insert the Sam and Max disc in my drive, and as I mentioned before, my DVD drive had failed on me, so my night was basically ruined. It really goes to show how even the simplest DRMs can easily screw over a legitimate customer (but something sure may have been up with me getting a Euro copy of the game :P I kid, I kid) as easily as Origin or something along those lines could.

Here's a wonderful example of the wonder of companies not using DRM in their games and how much better it is for customers, it involves my non-GOG jewel-cased copy of Unreal Tournament 1999 GOTY I got today. I installed the game, copied it onto a flash drive, transferred it up here, and played with ease, no CD or CD-key needed! Much better than having to buy a expensive DVD drive just to play a game that you have every last byte of on your hard drive!
Today hasn't gone very well. v_v Seems like that my true wake-up call to the evils of DRM. I knew it was useless and only punished legitimate customers for buying software from some companies, but I never had to really suffer from usage of DRM until today.
My copy of Sam and Max Season 1 still came with a kickass poster! :D But it's not really as cool provided it may just simply remind me of the evils of DRM, and that I have no way to play the games up here until I get a new DVD drive.

I don't think I've ever had one.

These days I have a simple policy when it comes to PC games with DRM. I don't buy them.
I also don't buy them new on console either (tho I have a PS3 and 360) because I'm not willing to support companies that employ those methods. I will buy some of them on console USED if the DRM on the console versions isn't too bad but that's the limit. If I miss out on some games that's a shame but I just can't bring myself to keep paying companies to do this stuff to gamers, yah know?

OK, that's Bioshock 2 off my "To Buy List". It may have been cheap, but it's not worth the hassle.

I'm busy playing Halo 2 at the moment and had no problem doing the once-off acivation for it. It's been pretty enjoyable thus far.

I've pretty much managed to avoid any nasty DRM experiences, but that's probably because I stay away from those "always online" types of games.

Bioshock 1, I installed it lately and it wants me to enter the cd-key whenever I want to play the game for authentification purposes.

When i first got on steam and didn't really no anything about DRM.

I bought Dirt 2 because it was very cheap on the sale. Little did i know it needed GFWL to play so when i actually did try installing it, it ended up downloading tons of updates and not working so i basically just though 'Is it really worth it?'.

Now i just really don't want any other clients installed on my system (Origin/GFWL).

Bought Zombie Pirates from GG a few months ago.
The damn thing refuses to authenticate.
It took GG 2 weeks to decide that the CD key they gave me is dodgy & I need a new one.
I'm still waiting.....

Holy!

I have another thread thinking playing a game that requires steam...