"The thing with an Open Mic is to use it as a 'live ' rehearsal , snd try to develop your technique with Microphones etc"

I agree. I have a love/hate relationships with open mics. Sometimes I find the fact that few people really listen renders the whole thing pointless. Sometimes I really relish that and take the opportunity to throw caution to the wind, trying out new songs I haven't properly prepared yet, or trying out fiddly riffs/ad libs I wouldn't dare to try in a pin-drop-quiet environment.

(Of course, there are some exceptional open mics that are great, where everybody listens, and the standard is just as high as at a folk club.)

I quite like the "entertainment" side of open mics: I'll tend to use the opportunity to try a few new covers.