Showing courtesy does not undermine you. It does not make you less than who you are and so it is necessary to show it whenever you can.
I want to share an experience with you. Few months back I was in a tricycle with two guys. An elderly woman stopped it and she looked like she was in a hurry but was hesitant to sit at the front. I dropped and sat at the front seat creating space for her behind. She thanked me and paid my transport fare.
Fastforward to last week when I went to a market in Aba to get goods for my shop. I heard someone tap me as I was walking and as I turned it was that woman. Turns out she owns a shop there at the market and obviously knew the nocks and corners better than myself. She didnt just offer to take me to places where I could get my products at cheaper rates but also gave me two very beautiful hand bags. When I tried to turn it down she explained that if she has started longer at the junction waiting for another tricycle because she couldn't sit at the front, she would have lost a huge contract.
Why not show a little act of courtesy today?