Which of these languages...

is the most worth learning, in your opinion, and why?

Russian, Turkish, Urdu, Punjabi, Korean, Hindi, Arabic, Chinese, Bengali.

Additionally, which countries that speak these languages are pleasant and which are shitty?

>>9
That's quite a stupid reason to not learn a language.
Russia is a shithole, but the language is still cool to learn. China is a shithole, but the language is still cool to learn.
Besides, maybe OP doesn't want to travel to the country. Maybe he just wants to learn a language.

I know Punjabi because I am Punjabi.
Not very useful to learn, but still fun nonetheless.