CDG is terrible. One of the terminals looks like some dystopian hell of crowding, squalor, and depression. Oh and obvious non-functional early 1970s design, but those things kinda go together.
I found the airports in China to be amazing. Great design, nice architecture, clean and modern. Sometimes flights can be 4 hours late for no reason though.
Flying out of Maracaibo 4 years ago (last time I went to Venezuela) was so depressing. No food or even water available, Long waits in various rooms for no reason, passenger stress super high due to a not insignificant fear that you may never leave or you'll shortly be extorted, or airport staff will steal everything you checked (not just valuables).
My wife travels for work to a number of interesting places, and I think she said that the airport in Sierra Leone is one of the worst. If you're in Freetown, the country's capital, to get to the airport you need to take a ferry or water taxi "speed boat" across the estuary of a river. That portion takes 45 - 60 mins and is not for the faint of heart. Then the facilities are as you would expect from a very poor country - not awesome in terms of amenities. Honestly, I'm not sure what level of corruption and attempted extortion she has to deal with, but I assume it's not insignificant.