Gamer problems 101.
If you have a hard time trying to decide what you want to play next, then Valve seems to have you covered: 'Play next' is the newest experiment added to Steam Lab.
"The Play Next experiment uses the same underlying technology that powers the Interactive Recommender, and applies it to your existing Steam library", Valve wrote; the Interactive Recommender is a tool that continuously learns from your play history and applies the result to the store to create personalised recommendations.
The newest addition to Steam Labs will suggest you three games to play from your own library. Should you not have an interest in the games it shows you, there's a quick option to reroll and get a new set of recommendations. It is a work in progress, however, "So don't be surprised if it sometimes shows you some unexpected comparison points".