The Forcefield.

So, people of different cultures smell different. Not bad, like "folks of nationality X smells awful" but rather people who consume different foods, use different soaps, and in general consume different cosmetics have different aromas. For example, in the northeast US during cold months African-Americans use more lotion to avoid becoming "ashy," and thus many have a lanolin smell due to their use of Vaseline Intensive Care and the like.

For a more concrete example: Westerners use colognes based on alcohol, whereas Arabs use colognes based in oil that smells spicier and heavier. (My wife and sister bought some, after convincing the clerk that they in fact were after the specific scent.) Thus if you get on an elevator in Qatar, you can tell whether a Western or Arabic women was the last in the elevator.

Separate from this is the issue of body odor. There are a number of cultures whose bathing practices are, well, more lax than those of the West, and thus in Qatar you will encounter folks who are neither Qatari nor Western who smell like gym socks. Not patchouli bad, but noticeably unwashed smelling.

One step beyond this are the forcefield guys. They are invariably men, and they smell TERRIBLE several paces away. When you see them in the malls, which are always very crowded, it is like they have a forcefield around them, such that the crowd parts and they have a 2 foot "no fly zone" around them. They have a forcefield of stank, which (if you are trapped in) should be the subject of a research project to weaponize. This is next year's NPRP grant. :)

Side note: I went to a dinner party tonight, and ran into a funny example of colloquial speech some Spanish speakers were discussing. The story was told that a kid was trying to say "I am very busy" but used the Colombian colloquial phrase which meant "Things are very tight," which heaven knows where they picked it up. This offended the kid's parents, as this phrase in Spain's Spanish means "I am making a lot of f*ck."

I love this kind of thing, because it calls to mind the following exchange:
"Are you very busy at work?"
"Yes, I am copulating a great deal."
"Juan, exactly what kind of physics department is that?"