Older hotel rooms tend to have dark carpet, dark furniture, and dismal lighting that would barely qualify to light a refrigerator. When entering a hotel room my first action is often to turn on every single lamp just because it's so goddamn dark and the master lighting is pathetic. Thankfully there's often a master switch to turn them all off when I go out.

It's getting better though, most new or recently renovated rooms have bigger windows, lighter colors, and stronger lighting.

If you're single and live alone, you'd likely find a hotel room comfortable. If you life in a dynamic household, a hotel room is like a cage at the vets office - boring, barely comfortable, way too public and lonely.

I'm a man and I find hotel rooms sad and empty. I, too, used to travel a lot. I spent a number of years living out of hotels in order to be at client sites, and I found them incredibly alienating. I can't be sure, though, whether this aversion to hotel rooms developed because I didn't like the rooms themselves, or because of my dislike of the travelling and client work. In either case, a decade later I still avoid travelling for pleasure at least partly because of my dislike of hotel rooms.

Have you tried renting renting residential homes (airbnb) when on vacation?

No, but the only vacations I've gone on since have been to visit people I know, so I just stay with them.

Even if I weren't visiting people, I don't think I'd want to stay in a real residential home through airbnb. I think I might lean towards a more business-y bed and breakfast place though, instead of a hotel.

I don't know how much "a lot" is, but I think that that can make a big difference, too. If, loosely speaking, you're home more than you're in hotels, then being in a hotel can be a treat; but if you're in hotels more than you're at home, then it's likely that you'll eventually come to think of the hotel as what's keeping you from home, hence the melancholia.

I got stuck in a hotel for a few days in Pakistan when they'd schedule the flights out of the country in the foggiest hours of the early morning/late night, and had flights canceled every day for a week. It was a trap - I couldn't leave my hotel much in case the airline called the hotel to confirm a flight was available the next day. The next town with shops was dozens of minutes walk away.

I think that it's an uncanny valley effect. A hotel room looks somewhat like a home, but it's definitely not a home. It's great not having to do your own cleaning, but the space feels over-cleaned and sterile.

Also, hotel rooms, during the day, tend to be where one is when travel isn't going well. I used to think five-star hotels were a waste of money; why would someone pay $300+ more per night just to have a fountain in the lobby? But now that many of my friends are having children, I understand it. If you're traveling with kids (increasing your likelihood that someone gets sick, or just exhausted) then you need the 4- or 5-star accommodations that you don't need if you're a young person who'll use it as a crash pad only.

Hotel rooms, then, are places associated with misfortune: travel ruined by someone getting sick, an unexpected layover due to travel delays, or landing in a city where one feels unsafe due to local conditions like crime or dangerous weather. If your travel goes well, you're only in one to sleep. If it goes poorly, you spend an order of magnitude more waking time in it.