I was sad, so I did this to try and make me happy :)
Russia: comforts you and hugs you like there's no tomorrow because he cares, especially for his comrades, you know(he'll even let you use his ushanka), sometimes he cries along with you
America: comforts and buys you lots of food to eat at home, like ice cream, burgers, fries, etc, tells you funny jokes and keeps you happy to keep you away from the sadness
Germany: comforts you, will wrap you up in a floofy blanket while watching a movie with you because he's the parent figure of the house and cares
Philippines: comforts you, will tell you jokes and reassure you, and keep making hugots(quotes) until you laugh so damn hard because they're so cheesy
Japan: gives you tissues and will cry with you, gives you an 18+/sfw fanfic of your OTP to make you smile
South Korea: will comfort you, let you listen to music to either cope with the pain or to make you happy, and will either give you a popsicle or a lollipop
North Korea: because he's a nice dude here, he'll give you lots and lots of adorable small nuke pillows and maybe even roses, will hug you because he cares ;-;
China: gives you pats, makes you tea to help, comforts you and tells you advice or that everything is going to be okay, it's just not the right time
Ukraine: will leave you alone at first, but will come back with a flower crown for you
Belarus: will give you the 'talk less, smile more' comfort method (SERIOUSLY GUYS I USED A REFERENCE PLS NOTICE IT- ;w;), or will take you up a hill/field with many flowers or trees at sunset, or will just give you privacy
Spain: comforts you, will play sad Spanish music to cope with the pain, or will just play sad songs on the guitar while you hug a teddy bear he gave you/ smell the roses on his garden (mostly he takes you outside at night for more comfort, so most of these happen outdoors)
France and Britain: both will ask you what's wrong, France will prepare some yummy pastries that are so good they'll melt your heart out, Britain prepares some tea and will give you advice, both will give you lots of hugs
Mexico: will play some music for you or attempt to make you laugh, sometimes he leaves you alone for you to have privacy
Canada: comforts you, cries with you while drinking maple syrup, gives you a maple syrup bottle plushie and a plate full of pancakes, he'll ask you if you want any maple syrup on them
Australia: comforts you, will let you play with hamsters/ any other animal you want to play with, and of course gives you water
Kazakhstan: comforts you, and the next thing you know you're flying with him
Poland: gives you privacy or comforts you
Indonesia: will let you eat his indomie while he's crying along with you (maybe because he had to give up his indomie lol-)
Malaysia: cooks up some food for you, and also be careful
Netherlands: will warm you up, cooks for you with no difficulty and without burning down the kitchen while you're watching a movie or something, and plays Minecraft with you afterwards cuz he belongs in the Nether-
And that's pretty much it, I think..
