"Can one really stop a thought from entering the head?"
Perhaps. Perhaps not. There is no absolute answer to this.
As someone who likes thoughts to freely flow through my head, I'm a rather unfit person to be answering this. However, I shall try to the best of my abilities and understanding- limited though it may be.
Most people are somewhat acquainted with the way they think, and the tendency for their thoughts to go down a particular line. Knowing that, it may be possible to consciously divert that flow, in SOME cases. What experience has taught me is that it is not possible to "not think" about something. Inevitably, your thoughts, instead of straying, will end up concentrated on what they shouldn't be.
What, then, do you do?
Just let them flow. And try to divert the flow, if you really must. Give them impetus and let them drain out. Transform them into another form. But no matter what you do, never try to quash them, for it is a failed effort.
You know yourself. You know how you think. You know that once your thought process has reached from A to B to C, the next stop will definitely be D. And D is something you'd rather not think about. You could end up being distracted at A itself, or at any other intermediate point. You may be able to shift your thoughts from A to E, because they are related in a different way. You could force yourself to think about H first, simply because it holds higher priority and it's your neck on the line.
But what when you've already reached C, and the train of thought is pulling out? You know that the next stop is D. There's no getting out of it; not when you're already halfway there. There's no intermediate stop. Sudden derailments are rare occurrences. So, what now?
Bide your time. Let the stop come and go. Do not try to alter what you cannot. And do not regret what you could have altered but did not. "What ifs" are a deep ravine, and scaling its sheer walls is no joke. So, try not to fall into it in the first place.
It's true; your thoughts do control you. But it's equally true that you control your thoughts.
"You cannot stop lightning. You can only redirect it."
(to all you Avatar fans out there- REFERENCE!)
You know you're already in the storm. You know you are moments away from a lightning strike. And you know that you are not walking away unharmed.
1) Let it hit you, burn you and destroy you to the bone.
2) Conduct it elsewhere and sustain minimum damage.
3) Do everything you can to get out of there and end up getting hit anyway, either by the lightning itself, or the collateral damage.
4) Pray that it doesn't strike you.
Take your pick.
Ah, yes; another thing. Do not burn yourself out in an effort to save yourself before the lightning has even struck. Unnecessarily painful and entirely useless.
It is a rare case, but not non-existent. Some storms can be avoided if you can make yourself believe the simple, but harsh, truth - they do not exist. It is only you who can see them, and you who created them. Their domain and power is limited to what you give them. They control you only as far as you let them.
No one else can help because no one else sees them. No one else sees them because they are not there at all.
Everything said and done - what do you do when nothing helps?
Find the eye.
And hope you emerge unscathed.
A.N. First off, thank you so much for the wonderful response. I'm glad you liked my work, and I hope you will continue to.
This was a request, of sorts. More of a question that needed answering. I hope I helped. Anything else; please let me know.
Please do check out my Tumblr and accounts too for my other works! Thank you!
Onyx out. :)