A coworker once spent half a day chasing down flickering lights on a whole floor. Turns out a stray neutral from an old remodel was just draped over a pipe in the ceiling, barely making contact. Every time the AC kicked on, the vibration would change the whole circuit.
Ever think about how many weird electrical gremlins are hiding in old buildings? I used to just blame cheap bulbs or bad wiring in general. Stories like this make me realize it's always some random hidden thing you'd never guess.
Man, that's a brutal troubleshooting hunt! It's like that time my uncle's porch light would dim whenever his fridge cycled on. Took forever to trace it back to a junction box in the crawl space where two wires were just twisted together with ancient tape. He kept blaming the bulb quality. How are you supposed to guess that?