You just blew my mind.

It is acually also the place were Wario got his name.

The name Wario is so brilliant now that I understand this. The flipped M is sort of a symbol for a character that is the exact opposite of Mario and then it also has actual meaning in Japanese... Mind blown!

This makes so much more sense now. I really thought that the creators were grasping at straws when they came up with the Waluigi

thats so weird and cool

I tried that. It didn't work. I typed, "悪いです"

In Japan, it's rude to bluntly say "that's wrong" or "you're wrong," so instead people say ちがうmeaning "your answer/this situation/etc. is different (from the right or expected one)" the part in the parenthesis is implied to save face.

When you use わるい you are bluntly saying "this is bad," which is sometimes warranted, but is usually just considered rude. わるい is more often used to describe things that are objectively bad, or at least something that won't embarrass anyone. You can say crime is わるい or the smell of poop is わるい, but even if it's true, you'd never say someone's cooking or accent or job performance or test scores or anything that might embarrass someone is わるい, even if you're talking about yourself. Instead, there are a lot of words and phrases to describe the "badness," in a way that is socially acceptable. ちがうis one of them, and I'm sure there will be more in future lessons.

ちがい just means "difference".

Thanks @V2Blast and @hotaruemi! You're right about the blunt and indirectly polite way of differing @hotaruemi. :D

"Mazui" is used specifically when referring to taste; eg, パンがまずい vs パンがわるい - "the bread tastes bad" vs "the bread is bad"