Laughing at people for no reason to make them feel left out

Me and some friends were looking for a specific street downtown, we were somewhat disoriented on where to go so we begin to ask the people around us. After receiving advice instead of a clear answer on how to get where we need to go we thanked the man and moved on. Two minuets later we had another stranger at are disposal this time it was different, i don't know what came over me but i just started giggling. Soon i was laughing at a perfectly innocent man who was just trying to be polite and give us instructions on how to get to a certain street. My friends thought the whole prospect was funny and started to laugh with me. This poor man though he was being laughed at and tried to sneek away, this action caused a even greater uncontrolled reaction of diaphragms experiencing spasms because at this point we all though the whole situation was so funny we were learning on each other for support and frantically gasping for air. We ended up finding prospect street soon after that.