Interestingly, I now unconsciously do this switching back to C:

(printf "%d" i)

Before I forget and switch back. I strongly suspect that the people who can't adapt are having difficulty because they are not programming with the new syntax full time. Practicing at night while the majority of your time is still spent with some other language is not the same thing. This is also true for learning human language and is why immersion programs are so successful.

Further, I absolutely do not buy the claims that people have that they can understand haskell easily but not lisp. Haskell might look more familiar at a casual glance, but its syntax takes a substantial amount of time to really understand.