Yack- I have noticed that some smells are VERY powerful triggers. Ex: Menthol Cigarettes. It took me a long time to make this connection.
For many years, I'd 'just be' in a bad spot. Often it was connected to the cigarette odor, even very faint.
Smells in general are very elemental and can invoke a strong emotional response. The combination of brown paper towles and a certain hand soap takes me back to happy memories as a kid, for example. I'm sure if a smell has a strong emitional component attached, you woulkd be much more senitive to it.