1. A thunderstorm that soaks all your stuff, AFTER you just left the hostel or town with gear dried out from the last encounter.
2. Having too much food (too heavy a backpack so it hurts!) or too little (so you starve and then have to parcel out food to make it stretch until the next resupply point)
3. The first one on the trail in the morning so you get hit with all the sticky spiderwebs. (don't you just love sticky stuff that hits you in the face?)
4. In the fall, all those acorns plopping like bombs and then creating a nice roller derby effect on the trail - sure to be an ankle twister if not careful.
5. Shelter and tent life. When newcombers arrive after 10 PM or get up at five AM. So much for sleep.
6. Shelter and tent life number two. When the late arrivers or early risers use their white LED lights to shine them full in your face or illuminate your tent. (be sure your headlamp has a red light feature)
7. Being too cold or too hot at night. Yeah, I like to be just right and feel good when I do pack the right things (but feel lousy when I don't)
9. Getting injured and having to leave the trail early. Boy I hate this. It's such a sinking feeling. But also a feeling of elation when you return all healed up!
10. Having to wait patiently for the next adventuresome backpacking trip. (but the planning is fun!)