Why would the trash man only empty two of my three trash cans?

Any sensible person would call Waste Management and ask them.

I just called them asked them why they didn't empty your third can.
They said " Because we don't like you beach ! "
I said " oh yeah !! You just come here and say that to my face you bastjerk ! "

He said " OK you little weenie , we will be there tomorrow morning and empty that can down your throat !
I said " OK, bring it on ! I will be here waiting for you , you low IQ moron trash truck driver ! "

He said " You bet we will be there ! "
I said " Yeah , ill be waiting for your lazy azzzzzzz ! "

So , you might want to leave for work early tomorrow morning.

How many arw you allowed to have? There's a limt.

In my city which also has Waste Management we have three different colors of cans and each color is picked up by a separate truck. If one of the drivers does not show up the cans he was supposed to collect are collected the next day.

Some places have a limit. Where I live, we can buy stickers to put on extra garbage bags or items (basically pay for them to take away extra). You might want to check with your city.