People who have studied proof-based subjects like math or physics tend to have a relatively easy time learning to program. Since computer programs are just a particular way of articulating proofs, it's just a matter of learning a new syntax, not a new way of thinking.
On the other hand, for those more comfortable writing prose, programming can feel challenging. Most often, people will complain that programming syntax is hard to decipher, but in reality I think they're reacting to the unforgiving nature of computers' understanding of what they meant (e.g. when a missing ; prevents a program from compiling).
While it's true that this is a syntax issue, I think the underlying mental hurdle is figuring out how express one's ideas in such a structured and explicit manner, since, at least for now, computers can't read in between the lines.