If you lose your secret phrase or passphrase, you may lose access to any accounts or data that are secured by that passphrase.
For example, if you have a cryptocurrency wallet that is secured with a passphrase, and you lose the passphrase, you may not be able to access your cryptocurrency anymore.
To avoid the risk of losing your passphrase, it's a good practice to keep it in a safe and secure location, such as a physical safe or a safety deposit box.