Sorry

Use sorry only in error messages that result in serious problems for the user (for example, data loss, the user cannot continue to use Salesforce, or the user must get help from Customer Support to continue). Avoid apologizing if the issue occurred during normal Salesforce functions. For example:

Avoid

Sorry, but you must supply a search string of at least two characters.

Better

Sorry, but you must exit and log in again.

Before you use sorry in user interface text, ask yourself if we could change the design to avoid the situation altogether. It's better to design a solution that doesn't require an apology.