Play Burger Shop, I found this game quite addictive. Other than that, I am also fond of Northern Tale and June's Journey.
I love all Dark Souls series very challenging game if you got a weak heart or you don't like to die thousands of times better don't play it.
multiplayer, i dont know, there are so many awesome ones, lots that just..went the sad way = ark, UO, wow was good too, but i mean, i personally am very fond of morrowind, the original, although i did technically play it first on the old box then pc later
GTA all of the series. Now GTA 5 is the best so far and the latest but I can remember GTA San Andreas back in 2005 it was off the hook, I bought a new PC just to be able to run the game.
OPENTTD. I really love it, it is a multiplayer version with improvements of the original Transport tycoon game. With regular updates, easy to download extra's and multiplayer functions. I play it almost every week. Official site: https://www.openttd.org/en/ (Not mine)
My favorite PC game was SimCity 4 w/ Rush Hour Expansion. That game occupied a lot of my time. I restarted regions all of the time - I tried to make my cities realistic. I named and zoned them as I would imagine real-life cities. It was cool. The SimCity debacle of recent was bad - I had purchased the deluxe edition.
RDR 2. This is my favourite game ever. Before the game came out on PC, I was playing on my old playstation 4 at 30fps. To be honest, it was not very pleasant, the benefit of the game itself is slow. But I was able to buy myself a new computer, and finally was able to enjoy playing RDR 2 at 60 fps.
The LucasArts graphic adventure's games. <3 (Indiana Jones and the Fate of Atlantis, Monkey Island 2: LeChuck's Revenge, Grim Fandango, Day of the Tentacle, Loom, Sam & Max Hit the Road...)
If you count "favourite" games by "ones I was most addicted to", then I will certainly say Dragon's Dogma and Rule The Waves.