High Level Programming Languages

When is it appropriate to use a high level programming language? Personally, I always feel guilty when using anything except C.

>>1
When i write C i write serious, long-term stuff that should use 100% of the machine cycles.
When the performance is secondary, anything else is fine.
C allows you to write at minimal abstraction level, thats why it feels more natural, since its simple.
Speed, Safety, Simplicity are like a triangle where you can't have all three:
Speed+Simplicity=Low-level Languages like C
Speed+Safety=Safety-Critical software like Ada
Safety+Simplicity=Functional programming