When you find yourself bored of your current game that you are trying to beat, what game do you casually jump into? Mine tends to be FIFA recently as it is a lot of fun to casually play when bored of whatever campaign game I am trying to beat.
Mine has always been a Mario game. I have own many games over the years, but Mario has always been something I've come back to. When Harry Potter was introduced to the world and they started making it into movies and games, I would play that as well.
Sims 4 surprisingly. All the controversy at it's start but I still find it a nice and fun casual game to fall back with. I mean it certainly isn't the best that the franchise has had to offer or anything like that, but I find that it has more personality than 3 ever had.