They’ve been streaming something (looks a little like Netflix) and took a break. My guess is Janis wanted a quick bathroom break so Arlo wandered off to the kitchen to get a snack that turned into something more. Finally Janis comes in to the kitchen to find out where the heck he’s been. He was enjoying his sandwich and chips so much he forgot about whatever they were watching.
Arlo watched something by himself, and Janis had wanted to watch it together. This is akin to Arlo taking a full plate of cookies that was supposed to be for both of them, eating them all himself, and then saying “Hey, I didn’t know you wanted any.”
I thought Janis was forcing the rewind button on life so that Arlo would have recognized his transgression and not do it or at least respond with an acknowledgement and apology for his error rather than a plain “oh, gosh. That happened, oh well.”
As to what exactly his transgression was …. well, Janis is a comic strip wife…
….
But I think DemetriosX explanation (as oblique as it is) is probably correct.
Another vote for DemetriosX’s explanation.
‘(looks a little like Netflix)’
No, that’s YouTube’s interface (or a simplified version, anyway…the part on the right should have more bits). Netflix is very different. (Of course that’s the desktop interface – complete with pointer – which is weird since they’re apparently using a smart TV or streaming box, given that Janis is using a remote.)
Comics I Don't Understand 
They’ve been streaming something (looks a little like Netflix) and took a break. My guess is Janis wanted a quick bathroom break so Arlo wandered off to the kitchen to get a snack that turned into something more. Finally Janis comes in to the kitchen to find out where the heck he’s been. He was enjoying his sandwich and chips so much he forgot about whatever they were watching.
Arlo watched something by himself, and Janis had wanted to watch it together. This is akin to Arlo taking a full plate of cookies that was supposed to be for both of them, eating them all himself, and then saying “Hey, I didn’t know you wanted any.”
I thought Janis was forcing the rewind button on life so that Arlo would have recognized his transgression and not do it or at least respond with an acknowledgement and apology for his error rather than a plain “oh, gosh. That happened, oh well.”
As to what exactly his transgression was …. well, Janis is a comic strip wife…
….
But I think DemetriosX explanation (as oblique as it is) is probably correct.
Another vote for DemetriosX’s explanation.
‘(looks a little like Netflix)’
No, that’s YouTube’s interface (or a simplified version, anyway…the part on the right should have more bits). Netflix is very different. (Of course that’s the desktop interface – complete with pointer – which is weird since they’re apparently using a smart TV or streaming box, given that Janis is using a remote.)