Words point to something beyond themselves. When you “accept” a thought, that means you have not resisted an arbitrary stopping point in the potentially endless signifying. But the last thought is not the last word is not the full story; it’s just a snapshot of one spot in the stream of meaning-making.  When does a “thought” begin and “end”?  Who is to say that a few mind-words constitute a full “thought”? When you “accept” the beginning of a thought but then redirect attention to something in the external environment, you very well may be nipping the thought in the bud. At some point, you decide to stop the spreading activation. That’s a decision – often a good decision. It’s not because the possibilities have been exhausted but that you’ve decided pursuing them is no longer worth it.