I have Steam. I play alot of games, at different times whenever I feel like it.
And YES I play multiple games at once, so Steam will tell you what I'm doing every time I click another game window! Cool huh?
Sometimes, people tell me: "Omigosh Metal, can you stop giving me notifs PLEASE its so turrdyy..."
Well, I'm not the one giving you those notifications bro! That's Steam!
But I WILL be the one explaining you how to get rid of those <annoying> notifications, okay?
First, you go to Settings in your Steam client.
Then, uncheck notifs that you dont like. Or if you really don't want any notifs at all, your window should look a bit like mine
Of course, this is just for the friends part. If you're getting all sick and tired of all the group notifications, there's not much I can do for you.
Therefore, the only option is to go to In-Game, and UNCHECK "Enable the Steam Overlay while in-game".
This will suppress ALL notifications you would normally get.
Ahhhh Finally... Some peace and quiet.
Yup, you're all alone now. Enjoy it.