This may be a more light-hearted blog, but it's a product of suffering and painful experiences. Here are essentials to bring with you on any trip -- especially to developing countries but also within the USA.
1. Sandals: These should be slip-on/off types. I love Chacos or Tevas. Essential if you enounter nasty showers, decide to head to the pool, need to visit multiple village huts for tea, or run into warmer than expected weather and a free evening to explore a town.
2. Two plastic hangers: If you need to "wet iron" something (i.e. sprinkle, smooth, hang, and let dry straight overnight), these are essential. Hotel hangers sometimes are rusted, often designed so they can't be used other than in the hotel closet, or simply missing.
3. Small flashlight: Essential for not disturbing roomates while trying to get to the bathroom at night, reading during power outages, finding the exit in an emergency, and more.
4. Hankerchief: I know you're worried about holding an accessory usually gripped by a senior citizen, but it's a swissarmy knife. Multiple uses include holding hot things, cleaning glasses or camera lenses, wiping the sweat off your brow after running to catch a plane, drying off surfaces (i.e. laptop after downpour), cleaning dirty dishes, etc.
5. Earplugs: Priceless if you want to sleep at urban hotels, concentrate while on airplane, or convey to others that you want to be alone.
6. Stomach meds: Middle of the night when the food poisoning hits? Good luck. Best to carry some pepto pills, immodium, and either a full dose of cipro or flagel.
7. Plastic grocery bags: Great for putting muddy shoes inside before closing the suitcase, using as laundry bags, protecting electronics against a monsoon rain, keeping food away from bugs, etc.
7.5 Great questions. Cross-culturally appropriate questions to break awkward silence or befriend a business contact include: what is the meaning or history of your family surname? what do you like to do with your free time? where have you traveled that you enjoyed most?
As an aside, I love these short videos of travel tips from author/travel warrior Dan Pink. Do you always bring something essential that is extremely useful? I'd love to hear about it.