I just found out how bad I am after doing a few videos of myself playing with the recorder I got recently
I did'nt realise how often I come in before or after the beats of the bar, and how much I fidgeted when playing etc.
But having said that, I did'nt realise some of the good stuff I was doing either, its now made me pay a lot more attention to what I'm doing when playing now and I can see a marked difference in the last few weeks.
I think I've fallen into this state of bad technique with not playing with a live band for neary twenty years.
When you play with a band, they are not long in telling you if you have any timing or other faults in your playing and then you sort them out. Or you "are" out
You do really need to keep checking yourself every so often, as you say, people dont really give you the proper feedback you need due to not wanting to offend you.
I have to say, I've watched and listened to some players examples on this site and others, and you'd love to say where they should change this or that but not wanting to offend and not really knowing the person, just keep quiet.
I'd rather have the bad reports in order to sort myself out, but not everyone is like that I suppose.
I was in a flamenco guitar site once, and you'd get some guys posting a video of them playing a piece and asking other members to be honest in their opinions. So when some members were honest in the negative response, the guy would blow up and cause such a rammy that the thread would eventually have to be locked.
So I guess its better all round just to keep quiet