Creative "POLICE" the ones who say you cant do that

Have you ever met any of those people who constantly say, "You cant do that ". Have you ever asked the question "why". Generally they will reply with " aaaaaaaa because, because you cant "or something similar.
Today I would like to tell you a story about the craft or creative police that lurk around me.
In the 1970's I started china painting, learning from an elderly lady, (whoooo someone older than me). A new lady came along to class one day and started painting a plate. Our teacher insisted we trace the design on to the item we were working on and apply the paint a certain way. The new lady said ok, and painted her plate. Well, what an upset, new lady had used the brightest oranges and purples on her plate, hadn't gone softly, softly blending colours. The plate was beautiful, for a beginner the work was amazing. Sadly new lady was kicked out of class, because apparently she broke the rules. How sad, new lady had upset the teacher by choosing her own favourite colours and applied the paint her own way. New lady is probably a well known artist now.
After that I started attending classes to learn all about porcelain doll making. We used pre-mixed china paints to paint the faces with. Well, one day I asked a question, "why cant we use the powdered china paints so that we have a better colour range. "Because we cant, they wont work". To me that made no sense at all, porcelain was porcelain and china was china. So me being me, decided to break away from the limiting colours in pre-mixed paint and mix my own colours. I never said a word to anyone, had the doll head fired. Then the questions started, "how did you get that colour?' Must have been where it was placed in the kiln, closer to elements probably, hasn't fired properly".
My reply "  I mixed the powdered paint myself and used a different colour to the pre-mix one".
Guess what, it didn't take long for everyone, including my teacher to learn how to mix powdered paints. Which they still use today.
Where do these people come from, why do they think there way is the only way a thing can be done.
One day, while I was teaching ceramics a lady came in and invited us next door to the studio to try out some new paint products they had. So off we went. We were handed paint brushes, picture, paper and paints to try and told "paint that. Thinking back it was quite funny. We both started to paint, when quite a large lady, the one in charge I think, came over, took my paint brush of me and 'said, you wont be able to paint unless you hold the brush properly", My reply, "ok". and returned to painting. A few minutes later back she came grabbed my paint brush and said loudly, "not like that, like this, you don't even know how to hold a paint brush ". My friend sitting next to me was getting a bit irate, and said "tell her who you are ". "no, its okay". Well, look out here comes the paint warden again, looking angry now. "stop, you are never going to make a painter, you don't even hold the brush correctly".
It was okay I had finished my picture, I never did tell her who I was or why I held the paint brush as I did. How dare this person tell me that I couldn't do something simply because I did not hold my paint brush how she thought I should. Reason is I have no right elbow so my arm will not straighten. I will continue this in post 2.