Warcraft Puzzles

Here are a few things about World of Warcraft that have been puzzling me.

• Why can I ride my Elekk through a giant bush or the limb of a huge tree but a bamboo tiki torch stops me dead in my tracks?
  
• Why can I fly all the way across Outland for 10s but flying half way across Northrend costs almost 2g?
  
• Why are some keys destroyed when you use them but some remain on your keyring forever?