system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does soap perfume/fragrance stick to hands and not wash off like other particles?

As far as I know, there are only polar and non-polar molecules, with  soap helping to dissolve non-polar molecules in the polar water. What  are these perfumes made out of to just avoid being dissolved in the  water and wash off completely?
gpt
The top layer of your skin is a porous, non-watertight material made up of dead, decaying skin.  Its only the lower, living layers that form a solid, watertight barrier.  This means that if you looked at the top layer of your skin under a microscope it would look somewhat like a sponge.

Anything that's a liquid flows into all of the holes that exist in the top layer of your skin and gets absorbed into it.  If there is something suspended in that liquid, like the the chemicals in soap that give it its smell then they'll get absorbed into your skin along with the liquid.  When the liquid dries out those smell chemicals get left behind.

People aren't very sensitive to the smell of most kinds of dirt - if your hands stink its probably because there is a lot of something on it.  On the other hand, people are really sensitive to the chemicals they use for imparting good smells into consumer products.  This means that when the soap washes away all of the dirt then there isn't enough dirt left absorbed into your skin for you to notice the smell.  On the other hand, it doesn't take very much of the soap getting left behind for you to be able to smell it.