I used to have a double monitor setup and would program / play games / browse around on primary while watching a series on my secondary. But since some years ago I noticed that I can't do both at the same time anymore. Definitely programming while a series is on the background is a no-go, but if I play games I also just entirely miss the series (or vice versa). Not sure if it has to do with getting older, or my prima…
In the past I watched shows with a friend occasionally, and he had a nasty habit of whipping out an iPad mid-episode to look something up. He didn't even pause. Sometimes he'd fall asleep as well. Then he had the nerve to say things about how the show didn't make sense or he thought there were plot holes. I didn't agree, and I assume he just missed major bits by splitting his attention. It's always bothered me when people put on shows (not broadcast TV, but things watched intentionally) in the background or on a second monitor and then claim later that they've "watched" it. The way I see it, if you don't want to really watch it, then don't. Go do that other thing that's on your mind. Come back to the show later. Or if it really can't hold your attention, don't make yourself watch it at all.