Neighbor told me my gutter downspout was flooding her crawlspace, and she was 100% right
So my next door neighbor Deb caught me at the mailbox last Saturday and said, real calm, "Hey, when it rains hard, does your downspout dump right at the corner of your house?" I said yeah, probably, why. She goes, "Because I think it's running under my crawlspace. I've had a wet spot for 5 weeks."
I felt about two inches tall. I went and looked and sure enough that downspout empties like 8 inches from the property line and the ground slopes her way. I'd walked past it a hundred times and never once thought about it.
Got a $12 flex extender from the hardware store and ran it out 6 feet into the yard. She texted me two days after the next storm that the wet spot was gone. Whole thing took me 20 minutes.
Point is I never would've caught it from my side of the fence. Anybody else had a neighbor point out something on your own house you were totally blind to?