This should be obvious but it's rarely put in practice. SO MANY PEOPLE DO THIS - and it's got to be the most frustrating experience for anyone around you. Look, we all deal with procrastination. I understand that we aren't exactly AI so we humans will second-guess shit.
But if you agree to do something or tell someone you'll do something for them - DON'T GHOST THEM EVEN IF YOU WON'T DO IT. Being up-front with your customers or community members just means being up-front with your fellow man. Hold this value with you. If you suddenly realize you can't or won't do something for someone else no matter the reason, just tell them so with as much advance notice as possible. Why? Because they will find out that you won't do what you said you would!
This is how people lose their best customers in an instant and never get them back. This is also how you lose someone you actually care about in an instant. If you talk the talk but don't walk the walk, be ready to destroy your entire reputation in an instant.