While doing electrical service work, my lead and I were sent on a call to a home with the information, "They got some lights done quit working. See can ya get em lit up." Upon arrival we consulted the homeowner, an older fella, in his sixties I would guess; who proceeded to brief us on everything he'd done and tested so far. He'd checked the switch, he'd made sure the travelers and common were right (see 3way switches for more info), he'd taken the fixture down and tested power in the box; both hot and switched.
I looked at Ralph, my electrician, and we just nodded knowingly. I went back out to our truck and got our six foot ladder (we *NEVER* use a homeowner's ladder), then ohmed out a good light bulb and stuck it in my shirt pocket. When I got back inside the homeowner was still discussing with Ralph, who listened patiently, what could be the problem. I set up the ladder and quickly replaced the bulb, and flipped the switch. Light.
The homeowner didn't have ANYTHING to say beyond, "Well. Looka there." Ralph gave him some face to save with the old "
sometimes the filament in there is broken, but not vaporized, and can still make contact intermittently and light up", but it was almost tangible how embarrassed he was; so we politely got the hell outta there quick.
I dunno where I was going with this, btw.
. . . "happens to all of us"? I guess? Maybe?