What do you consider the 5 most important languages a human being should learn?
 

I'm going with
Enlgish
Spanish
Chinese
Russian
French

I won't presume to know THE most important 5, but English is definitely at the top, followed by the language where the person lives, if it's not English speaking.

Most important for what, exactly?

The most important languages for general communication (ie. understood by the greatest number of people on Earth) are going to be different than the top languages for business or study.

If you wanted to be able to communicate with the greatest number of people in the world it would be

1) Mandarin
2) English
3) Hindi
4) Spanish
5) Arabic

I want to learn them all, but they seem so hard. I mean, Mandarin has so many characters, I mean gosh, do natives remember them all and use them often?

It's like saying "do native English speakers remember all of the words in the Webster/Oxford dictionary and use them often?"

I agree with you on those first 3, English, Spanish and Mandarin. The others mostly depend on where you wanna go or what you wanna do.

I'd say English at the top because that's pretty much the universal language used in international technology fields of development. And get real, the world in general doesn't really want to talk to the poor Chinese (except maybe for economic reasons) nor the Spanish speakers no matter the high numbers. Sad but true.

English
Chinese
French
German
Spanish

It all depends on which part of the world you are/or/going/and come from.

This is a pretty bad question in my opinion. It all depends on what they are important for. If you're thinking for International business (and which specific business you are in), Mandarin, I would think, would be very important, along with English. But if you are thinking more science related, maybe Latin and German. It all depends on what and who they are important for.