Can someone give me one good reason why this feature doesn't exist? The lack of this feature is what stops me from playing a lot of the time. I don't want to have to play EVERY SINGLE GAME with my friends who can often get aggravating, nor do I want to have to say "Hey, I'm not going to play with you even though there's enough room in the lobby simply because I'd rather play with people my level." So Riot, please, give this long needed feature a chance or AT LEAST tell me why it doesn't exist. Thank you.

I totally agree, I have been wondering why this isn't available for a very long time.

I concur. It would be greatly appreciated to add this feature. I understand how riot wants to keep the social aspect of this game, however sometimes I just want to grind some elo and just enjoy the game, or there is always one person you know IRL that always asks to play, and it's considered rude to say no. Offline function would help us out alot.