Three airports - TIA, LHR and JFK - that I very recently used are in the list.  I honestly did not think they were that bad as this article makes it out to be.

London LHR is quite big.  If you are travelling with kids, make sure to check in the stroller at the airplane door and make doubly sure that it gets brought back at the same door when you get off the plane.  They generally otherwise send it to the baggage carousle like your other checked bags.  Without a stroller, carrying an infant through seemingly interminable maze of what they call airport walkways can be a torture.

New York JFK is boring, but that's about it, I think.  People who work there are their usual nonchalant and not-rude but also not-friendly.

Kathmandu TIA is much better than few years ago.  Yes, I read about the bribe incident that recently occurred and my heart goes out to the victims.  Kudos to that Sherpa lady who brought this to light and those corrupt A-holes need to be put in jail for extended time.  Having said that, my experience at TIA was quite smooth and hassle-free.  The officials were polite.  Even the bathroom was decent.  Sure they charge Rs.160 for a can of Coke but other than that, not much to complain about.