Wendy loves to tell me what to do when I am playing games. Recently I have been playing a lot of Civilization 5 and she has taken to watching me play sometimes asking me to explain why I am doing things and sometimes to give me advice. You might think if you know the two of us that I would be the one who is constantly attacking the enemies on a relentless campaign of destruction and that she would be advising me to make peace; you would be wrong. She takes tremendous delight in ordering me to start wars with everybody and wants nothing more than to see me extinguish enemies completely. A little bit of conquest, taking some land, killing some soldiers, these are not enough for her; she wants annihilation.
I totally get the desire to watch someone play a video game and kibitz. It doesn't have to be a video game though, I really enjoy sitting quietly while people work on problems of all kinds. Just being silent, in the presence of a person who can talk sometimes but who is focused on a task I can observe is very soothing for whatever reason. There are some games that this does not work at all for like World of Warcraft or Portal, for example, but I love watching tactical games like CiV and roguelikes like Diablo.
I remember one person in university in particular who absolutely loved watching others play video games, so much so that he characterized himself more as a video game watcher than a video game player. He could talk with great authority about the tiniest minutiae of games he had never actually played because he spent hours watching people work on the hardest challenges those games had to offer. We all get that to some extent as I can talk at great length about Star Trek (despite not considering myself a fan of the series) and surely everyone else absorbs information in the same way from those who share their hobbies.