Is friendship fragile?

That question is always in my mind >.<

I always wonder as to what is friendship.
-What is the meaning?
-How to retain it?
-When is it considered a good/bad friendship? -Why is friendship important?
-Who is involved in the connection?
-Whom shall be blame/ acknowledge if something bad/good happens?

Doesn't it bother you?
Just the thought of it is stressful :(

How I wish I could return to the childhood days where there were less worries and more playtime~ All the questions above wouldn't matter much then~

P/s : Thanks to those who've shown me the ups and downs of 'friendship' :]
I've learnt and experience enough for me to be slightly smarter (?)

Nights~♥