Because Mark Bittman says somewhere not to worry about the pasta snobs who tell you not to reheat your pasta. He claims that they do it too.
Heat a fair amount of olive oil (maybe a T or so) on medium-high heat.
Throw in a little crushed garlic
and a smattering of red pepper flakes.
Throw in a handful of cooked rotini pasta and
a half handful of walnuts.
Cook a minute or so until it's heated through.
Smother in parmesan cheese.
Eat it up!