I know that there are many teachers who don't get observed after doing much preparation who feel as bad as those who were observed. You are correct that observations should be private affairs, yet the emotional reactions to being observed are also understandable. What is unfortunate is the view that one lesson observation, perhaps only lasting 30 minutes, can in any way sum up a person's whole teaching career. It can't and it doesn't. It is merely a snapshot. It is also best kept private because it simply contributes to a view on 'the teaching'. It helps inspectors say that out of X lessons observed, Y were outstanding, Z were good etc. If you get graded as good or above, that is worth feeling good about. If your grade is lower, then make sure you understand why and if you know that you are generally a good teacher, forget it and move on.