Patience is the key which solves all problems.

This happened with me once while coming back from office late at night. The time was around 11:30 pm and most of the public transport had stopped. 

It had been a long hectic day. I was pissed off and too eager to reach home and rest. I was on my bike. The traffic signal just before my house turned red and it aggravated me even further.

Then suddenly someone came up from behind me and tried to hand me a paper. I thought it was another one of those pamphlet people who hand you pages of some sob story and ask you for money. In my aggravation I shirked the person away with the motion of my hand without even looking at him. 
This guy moves over to the next person in traffic and does a similar thing of showing him the paper. The other guy who was not in as bad mood as mine looks at the paper and starts giving directions. It was at this moment I realized that the person who came to me was asking for directions. He couldn't speak so he had written it down on a piece of paper. He was not some beggar asking for money, he was dressed as a salesman carrying one of those bulky encyclopedias. After getting the directions he smiled at the person, bowed his head showing his appreciation and jogged away to the other end of the road.
  
I felt pathetic inside of me. By the time the signal turned green this salesman was standing at the other end of the road signalling people for lift. I decided to help him out but my house was on a different route than where he was asking for lift. I moved on but I was still feeling bad for treating a hard working person that way. After going about a 100 metres I decided to turn back and drop him off at his destination. That was the least I thought I could do to make up for treating him like a dog. I turned back and saw him still signalling at people for lift and showing them the piece of paper. I was about to reach him when another bike rider stops and decides to drop him off. As the salesman is reaching up to sit on the bike, he notices me in the distance. I felt he would recognize me and show me the finger. He recognized me but to my disbelief he smiles at me and waves at me as he goes away on the bike.

His gesture brought me to tears. Here was a man who probably had been walking all day, door to door trying to sell books even though he could not speak while I was sitting in an AC cabin in front of my computer. And yet I was the one losing my cool over nothing. 

This incident did not change my life but every time I am angry or frustrated it certainly helps me look at the silver lining.