People don't hold their hands out to Haruhi very often. "It's a promise!" she chirps, while her (empty!!!!) candy wrapper is tossed into the trash. Insouciantly she slots the coffee into the side of her bag, and only then extends her hand for proper shaking. If nothing else Haruhi has an impressive grip and maintains eye contact.

"Later." Turning her back on him she skips up onto the platform for her ride away.