Most people have, and when they do, they only do it once.
By the way, what is a 'whelmed' anyway? When you deal with a customer, you can overwhelm them with good service and quality. They will return to you again and again. Or you can underwhelm them, with poor value and weak service. You won't have to remember their name for their next visit to your showroom. A simple, single whelm is when you do neither under or overwhelm your customer. When you are just a ghost in their memory where you didn't stand out either good or bad. The customer, when they need glass again, will always try someone different, because they are looking to be overwhelmed. No question about it.
The simple key to success in our glass business, or any business, is repeat customers. And you earn them by consistently doing your over whelming thing. Be on time, leave the job site cleaner than you found it, clean the glass, be polite and neat in their home, stay quiet in their retail store or office. These are overwhelming things to do.
Underwhelm your customers by showing up late, not calling early enough when you have to reschedule or doing the minimum amount of work you can.
Think about it...do you want to do just this one job for this customer, or do you want the next job and a couple of referrals as well?
A glazier once whelmed his client
He was lazier and defiant
His work was so bad
His clients were mad
And never became compliant