Friends, supposedly

What happens when someone you are supposedly close to just decides to loose it, and does something totally unexpected and hurts you?
I've seen it happen, watched it happen and even experienced that myself. It's not the anger that eats us up, but the disbelief. When it happened to me, I just took it in my stride and moved on. I am really good at being cordial that it's amazing how I keep my mouth from splurting the demand for explanations.
People who do that are usually insecure and need to make a statement.
Trouble is, when the parties involved are friends, then that is a really lame excuse. Friends see beyond weaknesses, but it has to work both ways. Close friends are supposed to go way beyond that, meaning, they look out for each other, not rob the other when heads are turned.
No matter how bad we expect another to behave, disappointment and disbelief will still set in. Why, because of the friendship.
It takes all kinds to make the world - so cliche
BUT we still have a choice on how we move on from there - not easy -
If we cannot find the strength to move on, then we should quietly move away and keep things at a distance so that another such opportunity will not present itself to totally destroy the friendship. It will, because for anything to work, it takes two.
If the effort to preserve the true meaning of being friends is left to ONE person, then it's not a friendship to begin with.