A bit of homework can ease some of the irritations. Did CDG for the first time recently and even with the homework the layout was illogical. However the AF bus was OK going into town and the RER was VG coming back.
My pet irritation has to be NRT in transit & trying to make a phone call. No Jap change & no local phone card = no phone access to advise my destination of flight changes. Even the KAL lounge ladies with a fistful of cards couldn't get a phone call to Korea last time there. And the Jap dial tone won't let my laptop work ( though others seem to be OK)
Least irritating airport has to be Koh Samui in Thailand. No air conditioning, but no windows either.