I've been on tour with big name acts (male and female) who could not (after long careers onstage!) tell the sound person what kind of reverb they'd like (long decay/big room etc.); what frequency panel they'd prefer for their vocal quality; or what they wanted to hear, or not hear in their monitors. I usually had to play interference explaining to the sound booth easy directives like 'boost the mids, drop the highs' etc. just so that we could finish the sound check!
I once saw a concert with Petula Clark, who at that time had been a seasoned veteran for many years. Her mic cord came unplugged, and SERIOUSLY, she looked around helplessly until a tech came and plugged it back in! I was stunned at her lack of professionalism. I can't believe that she wouldn't know how to plug the mic back in, and it really was too stupid to chalk up to being a Diva!
I think it goes for everyone to KNOW YOUR EQUIPMENT, and know how to talk to your crew on a technical level. That's the best way to assure that you'll get the sound you want, and the respect and cooperation of those working being the stage to make you look and sound great!
