File this under "Harry's Not the Brightest." We all know that Harry is impulsive and not exactly the smartest tool in the shed, but this question may have a more logical answer. I'm gonna go out on a limb and say that liquid luck probably wouldn't be any good against the Dark Lord, as it's likely not strong enough to combat dark magic.
While we're on the topic of Harry being a bit dimwitted, let's talk about the Half-Blood Prince. Sure, it's possible that Snape's handwriting changed significantly over the years, but it's also possible that Harry's just not observant. Plus, he never really paid attention in Potions anyway.
If you've read Harry Potter and the Cursed Child (which you absolutely should have read if you're a true HP fan), you know that Harry's scar pains return when he's older. Just because Voldemort's dead doesn't mean that Harry's scar will never hurt again. Still, I do like imagining Harry's freakout when he gets a bad sinus infection or migraine.
I'd like to believe that there are wizards that can talk to birds or fish or rabbits. But let's be honest, all we really want to be able to do is talk to dogs. Puppytongue would be so much more useful and so much more fun than Parseltongue.
Madam Pomfrey can regrow bones, so I'm sure she's got something in the ol' medicine cabinet that can completely stop period bleeding. Or maybe young witches just buy magic tampons that never leak and can't give you Toxic Shock Syndrome.
Man. Students at Hogwarts really don't know how good they have it.
A lot of people have asked this question over the years, but J.K Rowling has a pretty good answer for it. Because she was so tired of people asking her to clear this up, she did what any good writer would do and took to Twitter...
This one's a brain-scratcher. But here's a bigger question: If you use Polyjuice Potion to have sex with a person who thinks you're someone else, did they technically consent? I think the whole Polyjuice Potion sex thing can pose some serious ethical problems.