Thor watches his entire storm system peter out because of one bad cloud. Mjolnir scolds him for hooking up the clouds on a single circuit.
This toon is based on those frustrating Christmas lights where one bad bulb causes the entire string to go out (yep, it’s that time of year). I’m not sure if those kind of lights are still around or not, so hopefully you don’t need to be an Oldy Olserson to get the joke!