Detachment from attachment?

I made a friend of mine almost cry yesterday (yea, notorious me :P)
How?
It was a casually said statement on complete detachment after college ends. And I never knew she was so attached to me. And I am blind to others who might be attached to me. I never got attached. I refuse to attach.

Ruthless and mean. An unannounced departure with no specific promise of return. Very unceremonious, ungraceful way of getting recluse. Queries are unanswered, and "gracefully" welcomed with curses when arrive unannounced again. I can see they care. And it is beautiful that some understand this flaw of wanting to go away in me now and don't misunderstand it. Had bad history on it :P

It all must be a self protection mechanism. Darwin's theory of Survival of the Fittest. If you don't develop a strong immunity to a recurring problem, you'll succumb to it. That is the theory. And it stands true. Probably once hurt and misunderstood made me build a strong impermeable wall. I am seeing me first and I don't want me to be hurt, again.

Result: Detachment from attachment.
Simple and doesn't hurt.
And I know this is not healthy or good. I cannot be like this, "unstable" sorts, especially if I ever fall in love, again.(With this rate? yea right!) One burn was enough for me :P