You make me feel old for realising people younger than me have not ever realised this. But it makes sense now I type it... out loud(?)

Back in my day the Steam UI was army green and you'd use it to play all the LAN games your mate had by copying their entire Steam folder over to yours a couple hours before the LAN started. And that was it. That was the "install". You had Steam and all the HL mods like DoD and CS. Primed and ready to get noise complaints from the neighbours.