Interesting replies! I suppose that I should be grateful that my own experience seems to be atypical of most travellers'.

Not to be unpatriotic, but I always thought that YYZ was simply terrible, and especially when it still had that horrible three-terminal layout. NAS also seems to have sanitation problems EVERY time I travel through it, and I can't think of anything more off-putting than the reek of overflowing toilets when I walk through a terminal.