Should I even bother learning...

...a second language?

I just want to learn one for fun, am I doomed to failure?

no youre not

just pick one out and in time youll get it :)

Learn sign language. If you learn it from videos/classes (not books), it's super easy to learn, and useful.

if you just wonna learn any other language id suggest a european language like French or German - if english is your first language then they are REALLY easy to learn (Ive heard the Michel Thomas CDs are AMAZING!) If you want a useful language go for Mandarin - but i warn you its REALLY REALLY hard, and ive learnt a few languages. Mainly the pronunciation.

Monolingualism is a curse. If you are Scottish or Irish, learn German. If you are English or American, learn French.

Monolingualism is a curse. If you are Scottish or Irish, learn German. If you are English or American, learn French.

Also, mandarin is not hard, it has a very simple grammar.

You have to choose what's less difficult for you: pronunciation or grammar.
Mandarin is hard because of pronunciation, French because of grammar.