Basically you don't need to think much about the computer itself, unlike C or C++. Just pass in your arrays or pointers (everything is passed by reference anyways), crunch numbers, and it'll be about as optimized as carefully __restrict__ laden C code.
There's also fewer traps to fall in than C++ which is elephant sized in scope to Fortran's mouse.
There's also fewer traps to fall in than C++ which is elephant sized in scope to Fortran's mouse.