Being a slytherin, I have found myself loosing more friends who might have been hufflepuffs. The most of them have admitted it was because I've hurt them in some way. What am I doing wrong? Has any other slytherins experienced this? I've had friends from other houses, but I usually have more issues with them than the hufflepuff friends. :(
To be blunt, if you keep losing friends you need to take a close look at yourself. How you act, what you say, anything like that. it could be something you are completely unaware of. If you are able to I would highly suggest talking to any of them and ask what caused ya’ll to drift apart or to not be friends anymore.
I have drifted from a good amount of friends myself, and it is usually a mix of different reasons. Usually along the lines of what our values are, they might be too different to remain friends. How ever I have very many near and dear friends as well, one of which is also my roommate and who is a Hufflepuff. Houses do not dictate how houses get along, it might be one of many causes but never the main reason unless parties involve are extremely superficial.