The only part I find “maddening” is when a source intersperses the ICAO and IATA codes. Not a big deal for my local airports - KIAD/IAD and KDCA/DCA, but confusing for places where the codes don’t match (EGLL vs LHR). I’d need to look up EGLL every time, since the 3-letter is what I know from ticketing/baggage.

But, that doesn’t really happen much in anyplace that matters. Usually just in casual conversation about airports/flying.