The 'not good enough' aspect has crossed my mind a lot more than once believe me.
But if your mic work with the first dance & cake etc got the desired results, the dancefloor was not only heaving all night but bouncing, you played all their requests even the crap ones , then got them a rousing sendoff at the end what more do they want?! What more could you have done? You don't just turn up either, there's little emails checking all's well before the event, wishing them all the best the day before, congratulating them again the next day...
Generally, I get at least one half of a couple thanking me profusely at the end as I'm packing down. To me that indicates I did a good job. Worthy of a review, hinted at in an email with direct links to Google & Facebook review leaving pages? Possibly. So why do less than half bother & even those only write a sentence or two?
. Now it may be that to leave a Google review you need a Google account & to be signed in. I know for a fact they're on Facebook because they've liked my page... So what's the deal?
It might be that they just don't like me as a person. Heck, I don't even like me as person half the time