Keeping your thoughts to yourself is not particularly desirable, or undesirable. Knowing what your thoughts really are, and what they imply, and whether you can stick by them–these are what count. If you’re impulsive and speak without thinking, you’re not showing respect for your own mind, because you’re not taking the time to really understand what you’re saying. If you avoid saying things that you have thought out fully, then you’re likewise showing no respect for yourself. Give your thoughts the voice they deserve–just make sure you can stand by them, first.