I've had a lot of bad travel experiences from traveling across the country and most of them involved the hotel. In Dallas I was in a hotel room that was crawling with roaches...same for a room in Myrtle Beach, SC. In Orlando my room was crawling with ants and really smelled bad. (I somehow seem to attract insects wherever I go, especially mosquitoes!!) In a hotel in South Carolina I booked a "whirlpool suite" which ended up having a thirty year old bathtub with a bubble making appliance attached to it. In Key West, the hostel I stayed at still had someone's underwear in the dresser drawer, among other personal items. If you don't stay in a nice place, the whole vacation can be ruined.
For some helpful hints on how to effectively complain about hotel rooms and make your vacation more enjoyable, check out my articles on how to complain about a hotel room under the Travel Tips and Information section on my site.