Triggers that Could Contribute to a Bubble Pop

Here is a list of tiggers that might occur in the next 12 months that would contribute to a poping of the bubble.

1. Rising fuel prices
2. Increased media coverage (already happening)
3. Tighter lending practices
4. Foriegners cut back on buying up bundled mortgages
5. Rising interest rates
6. GDP starts stagnating
7. A new hot investment category is found. Sucking money out of the housing market.
8. Natural distaster / terrorist attack
9. "upward valuations of the Chinese Yuan" (thanks commentator marutib)
10. Something Else? Discuss