Personally, I have never smelled ants, but I attribute this to never having had them in my house, only seen them outside.
Mice I have smelled and on doing so taken the matter up with the nearest cat and left it to deal with the matter, unless I could clearly see where the wretched beasties had got in to the house, in which case I block up the mousehole myself. (Not a service housecats offer, after all).
Freesias and every other flower I can smell quite clearly, but then of course how would I know if there was a smell I could not smell?
I am not away of having been asked, "Can't you smell this?"
While we are on the subject, quite often about an hour before dinner-time, I smell cooking. This is clearly imagination, as we live in a house, and the neighbours are just too far away for it to be their cooking I smell.
Do any of you smell things that aren't there?