Cancer is a water sign, the element usually represented by Slytherin house at Hogwarts. Gryffindor is most closely related to the element of fire (Hufflepuff to earth and Ravenclaw to air). However, there are quite a few Cancer traits that match up nicely with the average Gryffindor student from Harry Potter than not.
It's not a perfect match, but what is? Ignotus Peverell, the youngest of the brothers in the "Tale of the Three Brothers," and Harry's ancestor, has a birthday of July 12, and is himself a Cancer. Below we examine some of the best Cancer traits found in Gryffindor house, and a few that don't make a good match in any way.
Typical - Loyal
Hufflepuff may be the "loyal" house, but Gryffindors are the most likely to stand up and make a wall around you when you're threatened. When Gryffindors hear fighting words they are most likely to sprint for the door and take a look, see what they can do to help.
Just look at how many Gryffindors chose to stay back and fight for their school in the Battle of Hogwarts in Harry Potter and the Deathly Hallows and it's clear that loyalty of a very brave sort runs through Gryffindor house for sure.
Not - Imaginative
Luna is the most imaginative and creative character readers and viewers meet in Harry Potter and she's a Ravenclaw. Dean Thomas can draw really well, so there's not a lack of creativity in Gryffindor, just a lack of imagination. Gryffindors are traditional in their beliefs, where they see good and evil, how they view success.
They are very likely to fight for a new world but they aren't the ones who will design it. They find it easier to confront wrongs than to come up with ways to change them.
Typical - Moody
Gryffindors fight a lot among themselves. Look at Harry's dorm alone. Harry and Seamus argue for almost all of fifth year. Ron and Harry have one of their major falling outs over the Triwizard tournament in fourth year.
Then just look at Harry for all of Order of the Phoenix and watch how he keeps his feelings bottled up, refusing to really tell anyone what's wrong, and just being angry all the time. Cancer is known for being moody, and so is Gryffindor house, for certain.
Not - Persuasive
Cancer may be known for being persuasive, but most Gryffindors lack this particular trait. Harry can't get his own house to believe he didn't enter the Triwizard tournament. He can't convince his own house that he isn't lying about the return of Voldemort in Harry Potter and the Order of the Phoenix.
He even struggles to get students to the DA at the beginning because a lot of them just want to hear how Cedric died. Persuasion takes a calm personality that a lot of Gryffindors just don't possess. Gryffindors are a bit more into action and acting before they take the time to get a team set up behind them.
Typical - Insecure
Just think of Neville and it's easy to see that insecurity definitely has a place in Gryffindor house, just as it does in those born under the sign of the crab. Neville may seem like a bit of an outlier in Gryffindor, but then just look at Hermione who's Defense Against the Dark Arts exam in third year sends her fleeing after a boggart of McGonagall tells her she's failed all her exams. Then think about Ron who is always comparing himself to his brothers as well as his best friend, Harry.
There is a lot of insecurity floating around Gryffindor Tower at all times.
Not - Sympathetic
If a Hogwarts student is looking for someone to dry their tears and listen to their woes a Cancer is a great person to look for, but they probably shouldn't look for sympathy from a Gryffindor.
Gryffindors don't feel bad for Hufflepuff house when Harry's candidacy in the Triwizard Tournament overshadows Hufflepuff's glory. Seamus doesn't show any sympathy to Harry for what Harry has been through when he returns to Hogwarts after seeing Cedric murdered. Gryffindors like to act, not really listen.
Typical - Suspicious
Just watch Harry follow Malfoy around for all of sixth year in Harry Potter and the Half Blood Prince, and it's clear that many Gryffindors, like those born under the sign of Cancer, have suspicious minds. Consider Harry, Ron, and Hermione thinking it's Snape trying to steal the Sorcerer's Stone.
Consider the fact that Neville even sits up nights in the common room because he is suspicious of what Harry, Ron, and Hermione are up to and that, whatever it is, will lead to them losing more points for their house.
Not - Manipulative
While Gryffindor is usually a house of action, they are upfront about it. They don't work to turn others to their way of thinking, or convince them to a cause. You either believe or you don't, you're either a part of the team or you're not.
Gryffindors don't use their time trying to manipulate others to their side or into their way of thinking. There's good and bad in Gryffindor house, and you either understand that or you don't.
Typical - Sensitive
The strong, brave, jock house may not seem like a place where you would find the most sensitive Hogwarts students, but that's just not true.
Think about Hermione, and how she hides in the girl's bathroom first year because she doesn't have any friends. Just look at Ginny pouring out her heart in a diary, or Harry thinking no one understands him in fifth year. Gryffindor is full of sensitive students.
Not - Pessimistic
Harry may feel pessimistic after the death of Cedric and then the death of Sirius, but it's not lasting. Gryffindors are always working to make the Wizarding World better.
They go after the Sorcerer's Stone, rescue Ginny, free Sirius, announce the return of Voldemort (in the belief they will receive assistance). Gryffindors couldn't fight so well for the betterment of the Wizarding World if they were pessimistic.
