These days durood is considered a ritual. Whenever the Prophet's name is heard, people instantly utter: Sallallahu alayhi wasallam. This is not the real meaning of durood. The work done by the Prophet required great sacrifice. In this age, a person who believed in one God was pelted with stones. It was not today's age. These days you have religious freedom. 
The Prophet had to endure many atrocities. When he went to Taif with the message of one God and met the leaders, they ridiculed him and said, Did God not find anyone else other than you to send as His prophet?
The Prophet was a human being like us. He wasn’t a mountain or anything else. They said: Did God find no other person to send as His prophet? You seem to be an ordinary man. Today when you look at the Prophet's history, he seems to be a grand personality. But in his own time, he seemed to be an ordinary man. The leaders of Taif directed their young boys to throw stones at the Prophet.  They threw stones at the Prophet and drove him away until he started to bleed. He wasn’t offered food or drink. He was beaten and driven away. At that time, God sent the angel of mountains. He said: O Muhammad, I am the angel in charge of mountains. I can topple the mountains upside down. There were mountains on both sides of the town of Taif. The angel said: I have the power to join the mountains together and crush the people of Taif between them. 
What command do you give me? The people of Taif had oppressed the Prophet. When God saw this, He sent the angel to the Prophet. The Prophet replied: I want these people to be alive. Their next generations will be born. Among them I will find people who will accept the truth. (Sahih al-Bukhari 3231) The Prophet didn’t only restrict himself to the present, but set his eyes to the future as well. The Prophet gave many sacrifices, which resulted in a revolution. Due to this, human history came out of the age of religious persecution and entered the age of religious freedom. This is not a simple matter. There are thousands of such issues. When the Prophet's name is heard, you must remember that he was your benefactor. The greatest sacrfice was that the Prophet took humanity from superstitous thinking and into the age of science. He took humanity out of the age of religious persecution and into the age of religious freedom. The Prophet brought about a new age. This is why, we are sitting comfortably and talking. If you remember the Prophet's contribution in history and take his name, you utter the durood. The culture prevalent these days is nothing. It is simply lip service. 
Durood is to acknowledge the Prophet's sacrifice and contribution. People don’t even know about the Prophet's contribution. The person who knows the Prophet's historical contribution will exclaim: O God, send prayers to this person. Send blessings upon this person. This is the real essence of durood.