Mine is lilacs, because there was a lilac bush at the bus stop that I used to wait at with my mom when I was a kid, it was my school bus stop and the public bus stop so we spent a lot of time on that corner and now when I smell lilacs I just immediately feel like a kid again.
Aw I love lilacs too :) I planted lilac bushes along the side of my last house. We moved away this past fall and I really miss those bushes because they’d be blooming right about now. I hope the new owners are enjoying them!
My favorite smells are warm sleeping dog (kind of a cozy smell, hard to describe but if you know you know) and garage that is used to store cars (kind of a mechanical smell, not sure if it’s from gasoline or motor oil or what but I love it). And also I love the smell of strong tea :)