Snow
Although my plans were changed because of my stupidity (I hastily changed a flight due to snow) and snow, Hilton's customer service was fantastic, allowing changes and cancellations after as I was supposed to be checking in and allowing last minute reservations, and even spending time to figure how to arrange reservations for availability based on points. And, a local manager promised me a substantial upgrade that I was unfortunately unable to take advantage of due to the changed plans.