<human>: I'll start. 

I was a pretty strong guy from a relatively early age, so during freshman year of college I thought that a job in construction during weekends or so wouldn't be a problem for me. Anyway, one day I get called by my boss to go with three other guys (two 50+ of age and the other about 21-22) to put a 500+ pound full iron gigantic metal awning at a house. We had to install it, but because it was so outstandingly heavy and the window was pretty high up, we decided to put a metal rod on the wall, and then attach the awning to the rod while three kept it in balance and the other attached wall screws everywhere using a high end drill. So the four of us position, grab the awning, and on three we try to pull it up as high as we can. However it is still not high enough to attach to the metal rod. So while we hang in there with the awning hanging on our shoulder, we decide to give it one last push and heavy lift it. This time, however, one of the guys who was 50+ was also kind of fat, so when he tried to lift it the second time, he let out this really weird growl while his head got really red. For whatever reason, us two young retards thought it was an incredibly funny face so we start laughing our as off as a 500+ pound metal awning rests on top of our heads, hanging only with our strength. We keep looking at each other and we continue laughing like mentally challenged seals. The guy on the other side starts cursing at us and yelling that if we let go the thing would literally break our bones, if not cause so serious fatal accident. But we still keep laughing and we keep losing strength, and as the awning starts tilting and falling slowly, the other two guys decide to just fuck it and tell us that since we can't stop laughing we should just let it fall to the ground. 

We couldn't get it up for the next hour or so. The next day we were both fired for unprofessional conduct at work and for wasting time, as well as for endangering people on the job. 

So what's the worst time you started laughing?

Can you summarize the given text in a few sentences?
<bot>: Me and another guy start laughing while four of us are handling a 500+ pound mental awning over our heads.