Or it's just plain false that they all smell sickly sweet, but it's generally experienced because it's common to use mixtures of different gases only some of which have the smell, but since people normally don't ask about the specific mix (which is varied during the procedure anyway) they get the impression it's always that smell.
Reductionist and proud of it.
Being ignorant is not so much a shame, as being unwilling to learn. Benjamin Franklin
Chase after the truth like all hell and you'll free yourself, even though you never touch its coat tails. Clarence Darrow
A person who won't read has no advantage over one who can't read. Mark Twain