Why do people hate Hufflepuffs

What are the relationships between the Hogwarts Houses outside of the animosity between Gryfindor and Slytherin?

The books mainly show the Gryffindor point of view, but additional information about the relationships between the Hogwarts Houses can be extrapolated from Pottermore's "Welcome Messages" by JK Rowling [1].

Gryffindor - Slytherin

Open hostility from both sides:

Now a lot of people say that Slytherins and Gryffindors are two sides of the same coin. Personally, I think Gryffindors are nothing more than wannabe Slytherins. Mind you, some people say that Salazar Slytherin and Godric Gryffindor cherished the same students, so we may be more alike than we'd like to think. But that doesn't mean we're going to put up with Gryffindors. They like to hit us just a little less than we like to hit them.

Slytherin House welcome message

Gryffindor - Ravenclaw

Generally on good terms, although Gryffindors think some Ravenclaws are crazy and Ravenclaws sometimes accuse Gryffindors of showing off:

But he had hoped the Ravenclaws would have found it in their hearts to support him as much as Cedric did. However, he was wrong. Most of the Ravenclaws seemed to think he was wanted to earn a little more fame, by making the chalice take on his name.

Harry Potter and the Goblet of Fire, Chapter 18 The Weighing of Wands

The Gryffindors are fine. If I had any criticism, I'd say Gryffindors would rather Show-offs are . They are also a lot less tolerant than we do towards people who are different. In fact, they have been known to joke about Ravenclaws.

Ravenclaw House welcome message

Gryffindor - Hufflepuff

Very good relationship, even if Hufflepuffs are sometimes considered "too ordinary":

The Hufflepuffs, who usually had excellent relationships with the Gryffindors , had grown remarkably cold towards them. [...] It was clear that the Hufflepuffs felt that Harry had stolen their champion's glory; A feeling that may have been exacerbated by the fact that the Hufflepuff house very rarely achieved fame and that Cedric was one of the few to ever give them one after beating Gryffindor once in Quidditch.

Harry Potter and the Goblet of Fire, Chapter 18 The Weighing of Wands

Gryffindor (the house we get along best with)

Welcome message from Hufflepuff House

Slytherin - Ravenclaw

Slytherins are generally distrusted by Ravenclaws, who in turn are accused of being overly competitive and literal:

Well, you've probably heard of the Slytherins. You're not all bad, but you should be good to be on guard, until you know them well. They have a long history in the house of doing anything to win - so be careful, especially with Quidditch games and exams.

Ravenclaw House welcome message

We Slytherins take care of our own - which is more than you can say for Ravenclaw. Ravenclaws aren't just the largest group of Swots that You have ever met but also known for climbing on top of each other to get high grades while we are Slytherin's brothers.

Slytherin House welcome message

Slytherin - Hufflepuff

Slytherins utterly disapprove of the Hufflepuffs' lack of ambition. The Hufflepuffs share the other Houses' negative views of the Slytherins:

Merlin was a Slytherin. Yes, Merlin himself, the most famous magician in history! He learned everything he knew in this house! Would you like to follow in Merlin's footsteps? Or would you prefer to sit at the old desk of this famous ex-Hufflepuff, Eglantine Puffett, the inventor of the self-soaping tea towel?

Slytherin House welcome message

Of course, one would expect Slytherin to spawn malefactors as they have never heard of fair play and prefer to cheat every day before doing hard work

Welcome message from Hufflepuff House

Ravenclaw - Hufflepuff

Ravenclaws openly value the Hufflepuffs' friendliness, but sometimes fail to adequately recognize their accomplishments.

As for the Hufflepuffs, no one can say they are not nice people. Indeed they are some of the nicest people at school. Let's just say you don't have to worry too much when it comes to exam time competition.

Ravenclaw House welcome message

As you can see, we have produced more than our fair share of powerful, brilliant, and daring witches and wizards, but just because we don't yell about it doesn't get us the credit we deserve. Ravenclaws in particular assume that every outstanding achiever must have come from their house.

Welcome message from Hufflepuff House


[1] After sorting in a house, Pottermore users are shown a letter from JK Rowling in the form of a welcome message from the house prefect.

Although unfortunately there is no official Public links for each message can be any of four unofficial Sources can be found, for example in the Pottermore Wikia: Gryffindor, Slytherin, Ravenclaw, Hufflepuff.

Atayenel

There's also this little fact that the Slytherin house ghost murdered the Ravenclaw house ghost, what a little Can create distrust between them.

lfurini

@atayenel I think the real identities of the Bloody Baron and the Gray Lady and the connection between them are generally unknown to students.

Mat Cauthon

Great response with careful analysis of the welcome messages from the houses. This definitely deserves the accepted answer, hopefully the OP question comes back and accepts this. I will add a bounty after ibid expires.