We often refer to them as Monday morning quarterbacks. It's that slice of society that sits back, watches you try, and pounces when you fail. They offer their critique - about what you shoulda done, what you coulda done, how you woulda been better off if you'd...
Sometimes this Shoulda Crowd actually has some experience or expertise or credentials that qualify them to be your uninvited critics, but far too often they don't. They simply watch others try, struggle, build, work, strive, aspire, then chime in with their unwelcome offerings after the work is done.
Worse still is when the Shoulda Crowd happens to be those in positions of leadership.
The wisest leaders I know resist mightily the temptation to engage in Monday morning quarterbacking. Instead, they cheer you on as you try, they ask you good and guiding questions along the way, they provide solid support (both tangible and intangible) as you take risks and push boundaries, and they thoughtfully engage with you in reflective inquiry once the project/effort is completed (whether success OR failure) to see if you both can figure out what went right/wrong along the way.
Almost always I find myself thinking that the Shoulda Crowd shoulda kept their mouths shut.