This song make me happy:

https://www.letras.mus.br/a-banda-mais-bonita-da-cidade/1890483/

it depend on my mood.  

This time i like October and April  Rasmus 

https://www.youtube.com/watch?v=fygBE8dNawU

mine is Jackie Evancho - Lovers - "House of Flying Daggers"  ( https://www.youtube.com/watch?v=mhVWHDxdd-U) 

I can't choose ukrainian song because I like many of them 

these songs I listened almost thousand times:

China | 萧煌奇-你是我的眼 and 汪峰 - 春天里

France | Zaz - Si

Poland | Lady Pank (Many song: Stacja Warszawa; Jest taki kraj; Mój świat bez Ciebie; Zawsze tam, gdzie ty)

Japanese | デジモン - Butter-Fly (slow version) and Ayumi Miyazaki - Brave Heart

But it's not full list 

Beneth your beautiful  - https://www.youtube.com/watch?v=91-7YUp6VDM (Very beautiful)

Light my Way - https://www.youtube.com/watch?v=TUD4CQT33w4  (Very beautiful)

Andando sobre as águas - https://www.youtube.com/watch?v=ijTweJ1ZK1A ( I like to listen this to start my day)