I got a big slap in the face the first time I wanted to share my games with my son. I have a huge Steam collection, and he has a computer in his room. Suddenly I realized we both couldn't be gaming at the same time, even for different games, because all my games were in the same account. Suck. Tremendous amounts of suck.
If I had bought physical copies of those games, we'd be able to play them at the same time. But no, not with Steam. This turned my enthusiastic view of Steam into one of much more disdain.
GOG, of course, gives me no problem whatsoever, so ever since I discovered it I've been really pleased with it. I only wish they had a larger selection of games, and more of the newer games. But obviously that's not their fault.
I got an alpha invitation for Galaxy too, and was pleasantly surprised by it. It's really nice and convenient, so much better than the previous ad-hoc approach. So yeah, I'm only wishing I could abandon Steam for new games altogether. But the fact of the matter is, most games only come out on Steam. But I see GOG Galaxy as being the missing piece that might be able to take GOG more mainstream. Let's hope.