The person who made your day easier deserves more than being described as naturally helpful.

Calling someone a natural at helping turns their effort into a trait, and traits do not need thanking. It is a warm-sounding way of saying the work cost them nothing, which is almost never true. Somebody noticed, remembered, and rearranged something so your day would be lighter, and that is a series of choices rather than a temperament.

Say what the person actually did, in the specific, and say it to them. Then look for the next occasion to be the one who does it, so the arrangement does not settle permanently in one direction.