I really am annoyed at myself for those moments. They are usually more than moments. Sometimes ten or fifteen minutes go by and I realize I did nothing but entertain these useless thoughts. Useless is the right word, I am certain.
Most times, if I'm thinking about a possible future opportunity to say these things, I never get a chance to say them, or when the time comes, I say something totally different, something completely unrehearsed. Forget about the "I should have said's" - they are completely useless.
Today I decided I've had my fill of useless thoughts. I can do nothing until, and if, the time arrives. So, I will try, the next time I'm daydreaming about my wonderfully wise words, to pray as quickly as possible that they just disappear and allow me to use my mind for more useful efforts.
Lord, please clear my mind of useless thoughts, and guide my thoughts and words in the way you want them to go; I trust you much more than I trust myself.