Suggest you employ workmen you can trust and when they get there ~ shut up and let them get on with their job.
I never have this problem ~ but then I realise how much time is wasted by customers gabbing on as if they know what they are talking about.
Another good tip is to agree a fixed price for a job before they start and keep out of their way. All reputable workmen will agree to quote a fixed price before they start. If your chosen workman won't then I suggest finding another.