Always on display

One day in class ,my teacher shared a conversation he had with his dentist . While making small talk, the dentist asked what my teacher did for a living. My teacher said he teaches grammar .
After that, the dentist told my teacher about the time a fairly attractive girl came in for an interview to be a front desk receptionist.
The dentist said the interview was over when she began a sentence with "me and my sister" instead of my sister and I. Why was it over? Wherever my teacher goes to get his teeth cleaned wants someone at the front desk who knows how to speak proper English. My teacher shared this story with us as a reminder that we are always on display.
At first I thought, that's not really fair. After all, we're all human and make mistakes like that sometimes. If beginning a sentence with "my sister and me" was the only mistake someone makes at a job interview, should it really cost them a job? It also made me wonder , are we really always on display?
When I think of being on display, I think of those manequins at the mall wearing the latest clothes for shoppers to buy, or the animals at the zoo. I don't like the thought of being on display like that because I know I'm not perfect.
I know I tend to oversleep, drink more soda than I should, and sometimes say the wrong thing. I can be lazy , self centered, immature and I'm sure my friends and family can name more of my imperfections. As icing on the cake, as much as I love entertaining people , I don't want to have to be "on" all the time, although I know what my teacher said is true. But maybe being on display isn't about being "on" all the time; maybe it's about just showing the world what one has to offer.