Rebuys are just about the only purchases I make nowadays, and for them I usually wait for a sale, except for games I know and love, in which case I don't hesitate to rebuy at full price. The fact that I purchased most of my steam games for a pittance helps too. ;)

I always feel silly and robbed. If I new they would appear on GOG, I would just have waited. Of exactly 120 games on Steam, exactly 1 in 4 is dumped into my 'elsewhere' (mostly GOG) 'with less or no DRM' category (to put the number in perspective, I have 252 games on GOG at the moment).

Most of those 30 Steam games, I'd never have bought if I'd known they'd be released at GOG later. Sometimes, I myself am to blame, falling for cheap prices in sales (like the whole Legacy of Kain series for 5 dollar or so), but buying something dirt cheap while I know it's on GOG, only more expensive, just serves as a stepping stone to buy it on GOG later on the first time there's a sale for said games.

I often feel very, very stupid (many Steam-haters on GOG would probably agree, but to those who make a big fuss of absolutely boycotting Steam, I'd say there's much more important issues on earth: I'd love to completely boycot anything wrapped in plastic, anything flown in by plane, anything that's grown at the cost of rainforests or natural forests - approaching those ideals is all I can do, an absolute null-line is impossible to achieve. If absolute boycot's are impossible in far more important matters, why make such a fuss in putting zero tolerance on DRM? There's much more grieving things I'd like to ban).

Most of games I have in my GoG library I bought before as retails. Nothing wrong with that, I guess.
Unreal Tournament for example I have here, on steam, retail and.. on PS2 ; )

I have so much UT its not funny anymore... 3 retail versions and gog... also, i play Unreal 1 just because sometimes. I have a deep emotional attachment to that game.

I also re-buy here and delete from steam... Im an idiot but I believe more in GOG and CDP than any other company that exists right now.

It doesn't make sense to rebuy things you already have, no matter from where to where.

I have a copy of Heroes 3 on GOG here, I have zero interest to rebuy it anywhere else.

If I have a copy on Steam, it doesn't make sense to rebuy it anywhere else either as I already have it and Steam is cheaper than all....

Silly as it may be to pay for a game again, I do this for games I've purchased on Steam and found I really, really like and would definitely play again.

I own about 50 games on Steam that I either rebought here when released or got cheap enough on Steam as a bundle to begin with.

I do it from time to time for games I enjoy.

rare is when I'll do this.

I wouldn't buy another pair of sneakers for this summer identical to a pair I already bought just because they came out at a different store and had different packaging.

I have for a couple titles. advantage gog I suppose.

Imagine you want to live alone in a house and have a TV set that comes with the clerk selling it to you, always looking at what you do, sometimes changing settings while you are watching something or turns if off and take it with him for a few days (or forever). And when you say you finally have enough you'll still see him in outside mode, staring at you through the closed window and at one point when you don't expect and at least require it he suddenly is inside again, pulls the plug and ask for an id since after you moved to another house he have to be sure its really you.

Weeks later you see a TV set with all the benefits but without such a clerk in another shop :)

The super Matrix mode version of UT, with that lag! :P

Exactly
If you are one of those people (which for some unfathomable reason is many) that does not feel they are effected by Steam's DRM solution, then fine. Great for you.
But you're in denial if you think it will always be that way. Unless you plan to spend your life alone.

You think its daft to rebuy something you already own. Well, you're right.
But that is what Steam is trying to force me to do when I let my children or wife play one of my unplayed games.

At least this should be the Last time I have to rebuy a game.

I only re-buy Android versions of PC games I own. I don't re-buy on GOG but I appreciate getting a GOG copy for free. :)
In short, paranoid people re-buy Steam games at GOG.

Depends. Most of my Steam games from the past three or so years are from indie bundles anyway, and if I actually want a specific game, I'll usually buy it straight. If it's a AAA game, I'll probably have bought it for PS4 or Xbox One anyway. If it's indie, it's rare that it doesn't come to GOG. Most of the Steam-only stuff nowadays is shovelware.

But if there is genuinely a game that I have and value on Steam that comes out for GOG, sure, I'll pick it up from GOG in a sale, if I don't already have the DRM-free version through Humble.