bad weather
Also as one who has flown in a lot of interesting weather, I concur with Sasless -- he's spot on.
and to his advice I'd add the following:
There is no such thing as bad weather, there is just bad judgement.
What is OK for one pilot will kill another, and if you want to get better (whilst staying alive) always take the opportunity to fly with a more experienced pilot whenever possible.
NEVER be afraid to land, but make sure you take the time to check out the intended landing site. Remember if you are in a situation where you have to land, you will already be near your personal limitations. That's when you forget to look for wires, sloping ground, cows, and other stuff that will hurt.
DOn't forget about turbulence -- I crossed the Alps a lot in R22s and on one trip we had to make 3 atttempts (over 2 days) before I could find a slot in the weather due both to rain/cloud and strong winds. Gusting winds and a difference of 40 kts between ground speed and airspeed isn't much fun in the mountains.
SO don't be afraid to fail -- I for one have lost several friends to Get-There-Itis. It just ain't worth it.
Big Ls.