I have felt this way.
I too think about what to say and it sounds so good in my head until it comes out of my face! I think later I meant to say it another way. I feel it is good to share and I think it is a good thing to think about it later as long as we do not beat ourselves up over it.
I also do this that is not even meeting related. Someone at work says something and later I think, wow that would have been a good thing to say or add but the moment has passed. I tuck it away and hope it pops in my head next time if there is a next time.
It seems I make much better choices in life if I have time to mull it over. Then the answer comes to me and most of the time it can be so obvious, like DAH!!!!
Sometimes my wheels spin slow...lol
ETA: I have had people tell me here and there that I have made a good comment. And I think, I did? I am always surprised and wonder did I really or are they just encouraging me to share more often? What are those AA people up to???? LOL