Presentations of Self in Everyday Life

First impression.
It is said that first impression is very important when you start a new relationship with someone in life.
And there are more than just give them good impressions, it varies depends on who you are meeting and what role you will play.
When I was in Korea, I used to work at the kindergarten and was in charge of 7 year olds. I love children and love playing with them. So on the first day with them, I tried to be as nice as possible. They loved me for playing with them and became more friendly with me. But later on, when it comes to teaching, they seem to not care. They did not take seriousness of my teaching and I got upset. After realizing the seriousness of the problem, I have decided to be a strict teacher to them. It took me very long to get my authority as a teacher. That time I realized that I should have done this on the first day of class.
It is very interesting how people react to changes. When you are nice at first and eventually become demanding, you are likely to be ignored or hated by others. But if you are demanding and being difficult at first, people will appreciate you when you be nice to them later on.
What people think about me often determine myself even though it might not be correct.
Be true about myself. Be who you are. Be you. How can one express themselves fully by just being? I guess this leads to stereotype also. Sadly, even thought how much we hate to fall into certain category there is no way we can get out of being judged and fit into other's stereotypes.
To make a good impression there is only one way. We all know how to be good and what is good. But the key is can we keep on doing that?