Unfortunately, that's totally part of their culture. Everyone in a Japanese vocational school I went to assumed my close American guy friend and I were dating even though we've never held hands (then again, PDA isn't a thing at all here). I also believe it's a factor for the Japanese' low birth rate: they don't normally befriend the opposite sex unless they're romantically interested or it's a group thing that they got pulled into (they hardly split up and hang out in twos), so the opposite sex becomes a mystery to them, and dating becomes a scary uncharted territory or a chore.
Misophonia, lol.
Although that's a very popular explanation, I think their reason varies. Some say the slurping method is more delicious because they eat it nice n' piping hot while the air they suck in simultaneous cools the noodles down a little and they get a whiff of the food scent with every slurp. Others say that's how they've been eating it and they don't know any other way (I have a friend who is physically incapable of eating noodles quietly. She really tried). Most of the cooks in the ramen shops I've been to don't seem to react much whenever I eat their noodles quietly. Perhaps they're quietly surprised because it's unusual to them. As long as people finish their food, they're happy, methinks.
Okay, cliches I really can't stand:
1) "I will follow you to the ends of the earth... because I'm your butler / maid / secretary / manager / bodyguard / garderner / [insert any type or servant, second-in-command]"
I know it's real touching for a main character to have their Samwise Gamgee, but this writing is starting to look lazy. If they saw each other as friends or family they'd freakin' say they're friends or family. It makes you think that they live only for their masters like they're dogs.
2) "Actually... I... I really like y--" BOOMSHAKACHAKAWALAINTERRUPTIONYEAH
"Oh, thank goodness they couldn't confess their feelings to them! Boy, do I love that annoying interrupting piece of shit for ruining a good opportunity!" --- No One.
3) "Class, I'd like to introduce you to a transfer student." "Hey, it's that person I saw this morning / in my dreams / flying in the sky / on TV / in that alley beating up vampires!" "And s/he's gonna sit next to you." "Oh, no!"
4) The cold fish.
Characters who have a maximum of 2 facial expressions. They don't say much. Always secretly powerful. Always silver-haired.
5) Old/Ancient characters disguised as jailbait.
"No, I swear, it's not pedophilia! That girl is actually a 500-year-old vampire trapped in an 11-year-old body! She wears revealing clothes 'cuz she's mature like that!" --- Apologists
6) "I will do anything to protect.... that smile. That smile is the most important thing to me."
YOUR WRITING, JAPAN. IS THIS REALLY YOUR WRITING?