At Expedia, we know a whole lot about hotels. There are pros and cons to having all of this great knowledge.

On the plus side, we always can tell you whether or not a hotel is worth your money complete with a host of specific reasons why. One of the downsides: We know all too well about the WORST behaviors travelers can demonstrate when they spend the night at a hotel.

We decided to investigate some of these bad behaviors from hotel guests. The result was the 2015 Hotel Etiquette Study. As part of this study—conducted for Expedia by the market research company, GfK—we asked 1,022 Americans to weigh in on the most annoying behaviors exhibited by hotel guests. Consider yourself warned: The findings, which we released earlier this month, might shock you.

The most recent research project wasn’t our first foray into studying traveler behaviors; every year we conduct a similar study to tap current opinions on the most annoying airplane passengers. Our most recent airplane etiquette study came out in December 2014; we expect to release another one later this year.

In terms of hotel etiquette, the grand prize of most annoying hotel guests goes to “Inattentive Parents” who let their kids run wild. More than 67 percent of respondents called out these travelers as the worst of the worst, giving them a narrow edge over the second-place finisher, “Hallway Hellraisers,” who nabbed 64 percent of the vote.

Coming in third on the list of wildly irritating hotel guests were “The Complainers,” guests who berate hotel staff over minor inconveniences. They garnered 54 percent of respondent tallies.

Rounding out the Top 5 of irksome hotel guests were “In-Room Revelers,” with 52 percent; and “The Bickerers,” with 26 percent.

I have to be honest, some of these top findings concerned me for the way they seemed to target family travelers. I’ve got four kids and I frequently travel with them. I’d like to think they know how to behave in hotels, but sometimes kids will be kids. Does this mean other travelers have pegged me as an “Inattentive Parent,” or someone who aids and abets “Hallway Hellraisers” and “In-Room Revelers”? It probably does.

Other findings

That said, some of these behaviors are super-easy to avoid if you can just be considerate.

Take “Poolside Partiers,” who got 22 percent of the votes for most annoying hotel guests. One way to avoid being labeled one of those is, simply, to keep it down at the pool. Also, if you keep your drinking in check, you don’t have to worry about being a “Business Bar Boozer” (which garnered 12 percent).

Then, of course, are the travelers who can’t seem to keep their libidos in check after they check in to a swanky hotel.

A whopping 21 percent of survey respondents—just more than one out of every five—said “The Loudly Amorous,” or indiscreet lovemakers, were the most annoying hotel guests. What’s more, 20 percent of respondents said they find “Hot Tub Canoodlers,” or amorous couples in public hot tubs, to be the most irritating.

I’d tell these travelers to “get a room,” but even when they have one, apparently they still create quite a stir.

Tipping, toiletry theft, room service

Our 2015 Hotel Etiquette Survey culled data about a variety of other hotel behaviors, too. Tops on thast list: Tipping. Though 51 percent of respondents said they tip the hotel housekeeping staff and 31 percent said they tip the valet, an almost-incomprehensible 27 percent of respondents reported that they “do not tip” hotel employees at all.

To put this a different way, about one out of every four travelers don’t tip anyone at a hotel, ever. When you stop to think about how many hotel workers rely on tips for the bulk of their salaries, this data point is alarming to say the least.

Equally alarming were the stats that 26 percent of respondents have hoarded toiletries to take home with them, and 8 percent secretly have taken items from their hotel rooms.

(OK, I admit it, I’ve committed at least one of those last two faux pas.)

Finally, in what I thought was the most hopeful findings, our data revealed that 74 percent of survey respondents still consider room service to be a luxury, versus 26 percent of respondents who said they deem it “a necessity.”

To me, this last stat indicates there’s still plenty of romance involved with travel. Not even inattentive parents and hallway hellraisers can ruin that.

What do you consider to be the worst behaviors by other guests in a hotel?