Saying you’ll be there is a contract with no paperwork. Break enough of them and nobody signs with you again.

Commitments are enforced socially rather than legally, which makes them easy to break and expensive when you do. Nothing happens the first time. What happens is slower: people stop planning around you, stop extending the first invitation, stop treating your yes as information. By the time you notice, the change has already been made quietly.

Be harder to get a yes out of, and then keep it. If you cannot make something, say so early rather than letting the day arrive. A clean no costs almost nothing, while a silent absence costs more than it looks.