There is not much to specify for the question, its really simple: Which title is the first game you have purchased on Steam? Was it a good decision? How much did you pay? When was it and what device? You don’t have to answer all questions, this is just a fun discussion to have.
You can check your history: https://store.steampowered.com/account/history/ Edit: Some in the comments pointed out that the purchase history doesn’t go back all to the beginnings of Steam. So if you purchased something earlier, it won’t be listed on your account.
(I reply with my game too.)
watch dogs 1 for $5. Couldn’t (didnt want) to play it on mouse and keyboard it was annoying and not made for that at all. Waited a year till i could afford it and got myself an oled steam deck to play it (way before it got expensive). Great decision now addicted to my steam deck.