Oh, I know that feeling all too well. It is like one tiny mistake in the field can send a whole week off the rails. You spend all that time getting a detail perfect, and then one wrong number from a survey makes it all useless. It reminds me of how in life we can spend hours working on something based on bad information and have to scrap it all. The real trick is learning to double check those starting points early, because a little bit of time upfront saves a whole lot of pain later.

Friend of mine had a similar issue with a tricky drip, turned out to be a tiny crack in the plastic dip tube that wasn't visible until he took the whole thing apart. That $12 part fixed everything after months of frustration too.

Three emails with no reply means you basically ghosted a guy who was actively trying to give you money. Your best move is to send him a handwritten apology note this week, no excuses, just "I messed up and I'm fixing my system so it never happens again." Then follow up with a gift card to a lunch spot near his office, enough for him to take a client. Did this after I blew a lead from a builder at a golf outing, took me six months of small consistent touches to get back in his rotation. Make it about what you learned and how you'll make it right for him going forward. That's your only play now.

Three mechanics I know have all told me the same thing - people skip the little steps like that and then act surprised when something fails. It's kind of like how everyone forgets to tighten their gas cap until the check engine light comes on.

@paule53 makes me wonder how many of us are overthinking this stuff daily.