Let it not be said that I never accomplish my goals: I did read the entire Harry Potter series. A few different topics jumped out at me as I was reading, and I thought, wow, I could write some really insightful and amazing things about these books... if I'd only read them when they actually came out. By this time, I figure, most elements of the Harry Potter world have been beaten like destroyed horcruxes. However, I will take a stab at one thing that bothered me during my reading. I won't even Google to see if it's been done before because I don't want to discourage myself.
Please take note that whenever you read any commentary on a fictional piece that you have not consumed in its entirety, you may encounter spoilers!
I don't think most wizards "get" haircare. I cannot tell if they feel they, being so much more powerful than muggles, feel they are above that sort of thing, they simply prefer a more eccentric look, or they're just clueless. Hermione's hair is described as "bushy", Hagrid's hair is constantly tangled, and every time Snape comes on the scene we have to read (again) about his greasy, greasy hair. The only characters who seem—from Harry's perspective—to have their hair game down are either witches who Harry has the hots for (like Cho Chang and Ginny Weasley) or wizards who are vain jerks (like Lucius Malfoy and Gilderoy Lockhart).
This was all very confusing to me. Is magical power somehow tied to one's hair? Does Hogwarts have a secret motto that says "The poorer the hair, the more potent the spells"? I thought longer and harder than I should have, and I think I came up with a decent explanation: Harry just has no idea what proper hair looks like. I bet Hermione's hair isn't bushy at all. It's probably lovely and voluminous (let's not even think about that voluminous hair's transformation on screen). And Snape? Wizards, please don't hate on Snape just because he's been cooking up a cauldron full of deep conditioner. Maybe if Harry tried some he could get his hair under control.
Hagrid's hair is definitely a mess, though.