In each single one of us, lies a stranger, someone we don't recognize, we do not know, he steps in occasionally, says hello, sits and has coffee with us, we talk, but then we never introduce ourselves to each other. He makes decisions on our behalf sometimes, most of the times those are the one's we regret..simply because it wasn't us who made them, it was that stranger within, that which we don't know, and yet, we permit him to become us for a brief moment of time. Some people are very accommodating..they let him take over longer than he should, and as a result their lives are never normal again, or take longer to repair.
This stranger has all the time in the world, he has all the means, all the will, he knows you very well, he knows when you're vulnerable, when you're weak, he lends a shoulder, gives a hug, but in doing so..he doesn't save your life, he might even be doing the opposite.
That stranger steps aside..disappears, whenever you sit and ponder..on how you could have done something, or not have done it..regret is the awakening of you, the realization of that foreign being within you, who took control and made decisions.
Some people lose their reality, and become that stranger, hence the saying: "you've changed" which by the way is a nice song, I like the version by Eva Cassidy, check it out if you can.
I have my stranger too, and I'd like to think that I still haven't reached the point of him taking over me completely, he takes over me sometimes, and makes decisions, ones I regret, but thankfully they're not irrepairable. Strangers know when to stop, and what their limits are, and the more space you give them, they'd double it and move forward.
We all have strangers within, keep yours on a leash, because you can never lose them, or should I say they would never lose you.
One last note; strangers of the same kind also exist around you, the good thing about those is that you have the choice to lose them, even if they have all the intent not to lose you.