Guests at five-star hotels are four times more likely than guests at less expensive hotels to say they always overpay. More than one-third of them say they have had a hotel experience so bad they have cried, and one in five say their experience was so bad it ruined their vacation.

So says Provo, Utah-based experience management company Qualtrics, which surveyed 1,000 recent hotel patrons for its Hotel Pain Index. To gather the data, Qualtrics used a “statistically significant panel of people” who are regular guests at hotels to determine factors that most improved or diminished their hotel stay.

“Guests at very nice hotels have very high expectations that they will have an incredible experience,” says Mike Maughan, head of global insights at Qualtrics. “While hoteliers may feel they are providing an experience at that level, it’s clear that there is a gap between what people expect and what they are actually receiving.”

Dirty rooms are the single biggest factor in people having a negative experience, Maughan says.

Other findings: Hotel guests prefer free Wi-Fi to a complimentary breakfast, and the most desired hotel amenities are an on-site restaurant (86 percent), parking (83 percent) and a pool or spa (68 percent).

“In the survey, we see that guests don’t think hotels put a lot of effort into providing a great guest experience,” Maughan says. “About 35 percent of overall hotel guests feel the effort is lacking. It’s easy to focus on the glitz and glam of a place, and fail to remember that if the fundamentals aren’t taken care of, then none of the rest matters.”