That older surveyor who caught my baseline error on a Friday afternoon

I was marking out a small retaining wall job near Tacoma last fall, about 40 feet of run. I had my total station set up and I was pretty sure my baseline was square to the house. This old surveyor, must have been 70, walks over from the lot next door and just watches for a minute. He points at my backsite rod and says, 'You're about 3/8 off, check your prism height.' I rolled my eyes internally, but I checked anyway. Turned out the tribrach was sitting on a crumb of old concrete, just enough to throw the whole angle. He didn't lecture me or anything, just nodded and walked back to his truck. That one sentence saved me from pouring 2 yards of concrete in the wrong spot. Anyone else have an older pro quietly catch something small that would've been a big problem later?