I have often heard that the most compelling of the 5 senses is olfactory. Sense of smell can be incredibly powerful, and it's so easy to be transported to another time in your life by exposure to a scent which is very similar to something from earlier in your life. Smell imprinting is a mind-boggling thing.
I was walking near a grade school in at city in Belgium once, about age 22, and I smelled bread baking that was a dead ringer for the scent of bread baking at the school in which I attended 5th & 6th grades. It was a very cold winter day, and the heady yeasty smell was glorious, even though I never really cared for the bread in the cafeteria. It was just a fragrant snapshot that seemed like a time machine.
I don't think mimeographs are done in schools any more, but those of us who are old-fartish will remember the halcyon pre-photocopier era of school in which all our tests and class handouts were printed in the office on a bulky and loud dinosaur of a mimeograph machine. I would always volunteer to help hand out the stacks of mimeos, because they were cool to the touch, slightly moist and perfumed by the mimeo fluid, which I found heady and oh-so-pleasing. Yeah, yeah. That's probably why I couldn't have babies, right? Whatever.
Then there's that other fragrance of yore which I'll never smell again, but which I found delightful all those years ago. Gather round children, and marvel at the thought that gasoline used to only come in leaded. Leaded gas had a strange and distinctive odor which was glorious in small doses. I wouldn't want to be locked in a small airtight space with the stuff, by any means, but even though I was a kid at the time I always liked hovering near the gas pump when dad filled up the car, or at least hanging my head out the open window and taking a nice deep whiff.
I feel a pang of remorse for the aroma treasury which has been snuffed forever by freaky-outy environmentalists and a government run amok.