True friends are those that stand with you when you need them, even if you think you do not need them.
It does not necessary need to be huge collapse to see who is your best friend, but yes, it i perfect time for that.
Life is full of bad and good moments, you can easily see who is with you in your bad moments.
Not too many people are ready to sacrifice something for other people, without expecting something in return. Thats why true friendship is rare.