Can I help you?

This question can be very helpful at times, and most of the time it´s really welcomed. But what happens  when you are looking for that help and you get nowhere?
In my case, I try to keep going as far as I can, and when I finally get tired I post it somewhere, like when you do in facebook or other places. Sometimes you can only get so far with this question, and then you´re on your own.
Nothing, can be more frustrating than asking this question over and over again and end up at the same place. You think maybe next time I´ll get better or someone will get that answer for me, only to find you never moved an inch.
And sometimes you move farther because you got what you needed and then you wish you can return the favor. And I try, when I can.
It´s okay when you are in a big store and want something special, then "Can I help you?" leads you to the right place. Or let´s say you go to a place where they sell shoes and there´s no one close by, or they are busy with someone else, then you wait for that line for a couple of minutes or so, and if you get no answer, then you´re right out of the door.
Sounds simple and easy, just to walk away, and it´s okay to ignore it every once in a while, as long as is there when you need it most. Now, I seem to get rambling on the subject and getting nowhere, so excuse me if it appears redundant but that´s exactly how I´ve seen it in real life.
Never knowing when it´s going to come puts me on my nerves and I guess that when it´s comes naturally from other person, then you feel safe and you move forward.