Sending off a request to Steam Support is exactly what you do. So long as you're not expecting any compensation for the loss, they will gladly remove a title from your library permanently.

yes, contact steam support, they can do it

Don't think so, Origin had that option to hide some of your games

Why exactly would you want this?

For the bundle games, if it was from a multi game key, they can only remove all or none of the games from the key.

While Steam Support does not "like" to make these sorts of changes, they will infact remove an item from your account if you request them to do so and have a legitimate reason. For example, I was on of the unfortunate souls who purchased APB (All Points Bulletin) before Realtime Worlds went "bankrupt" and shut down the MMO servers, rendering the game unplayable. In this circumstance Steam Support was glad to remove the item from my account. On one other occasion I had the Duke Nukem Forever "Demo" removed from my account so I wouldn't have to be reminded of that horrible piece of garbage.

Is that what I need to do with Gotham City Imposters, which I've never played, bought, or even installed? :/

Nope, I just add all the games I play to the "favorites" and minimize the rest of the junk.

You can try contacting Steam support. There will be a 50/50 chance of whether they do it, mostly depending on what sort of mood the support person is in. Also, they'll probably yell at you.

Why would you want less games? Lol

WHY ?!!!

Pfff, you can create a category "dump" or "games off" or something, and minimize the category.

Yes

I accidentally installed SteamApp9, which automatically ties everything free to your account. I contacted Steam support and gave them a list of the apps with their appids that I wanted to remove, and a few days later the deed was done.

Weirdly enough, a few days after that somebody from Steam support responded (I forgot to close the ticket) and said that apps can't be removed from a Steam account...even though somebody else did...and other people have done so before...weird.

I've had them remove 'Low-Violence' versions of games (AU purchase) from my account so I could redeem a USA Full-Violence copy. They've been more than happy to assist.

Add games you want to hide to a category, and just don't open that category. :)

If you are ashamed for playing 299292 hours of bad rats here is what you can do:Disable internet,play the bad game for many hours.When you are done you exit the game and start teh internet.Voila.you played 23912312 hours without being recorded.

Like some people already said. Right click on any game > Set Category > Create a new category where you dump your unwanted games > Click on the + in your games list to hide the entire list > Move every game you don't want to see anymore into that category by checking the box in the "set category" option. Et voila. :p

Put them in a category and minimize that category. Something like: "Let 'em dust" or "Never ever going to ever play" or "Fuck this" or "nope" or "You guys suck" or "Cellar" or..

go outside

"You are what you play" Still not enough reason to want less games in your account.