You can always say something that you haven’t said. But you can never undo or unsay something that you have already said.
Be careful with your words. Be thoughtful, kind, and uplifting. It may feel good to say what’s on your mind, but it could be potentially damaging to your long-term relationships. Learn to bite your tongue and tactfully say what you need to say, when you need to say it.
This is not to say you can’t thoughtfully critique anyone (especially those you care for). If you don’t speak up, how can they make a change? But don’t say something in the heat of the moment, or else you may regret how it comes out – and what is said cannot be unsaid.