I had such a thought (it related to something that was true 20+ years previously but wasn't anymore when I was having the thought) and began to look at "when" I had the thought, what I was doing/thinking so I could see what purpose the thought served. It turned out I seemed to think it when I didn't know what to say to another :-) and wanted to start a conversation; it was kind of a what-do-you-do-when-you-don't-know-what-to-do response.

I worked on fixing the initial problem that was "causing" the thought and the thought went away because it wasn't needed.