I didn't reach my goal... What should I do?

Set a goal to, say, run for 30 days in a row? Only managed to run for 10 days? Sad that you didn't reach your goal?

don't be sad

I believe you feel bad, but 10 days out of 30 is more than zero. So even "failure" in the goal is a positive result, because the knowledge you have acquired does not disappear.

You tried. It didn't work. Try again, just aim a little differently.

There is no need to grieve over losses when losses are also lessons. After all, one way or another you learn something new.

"A five-minute sketch is better than none."
– Danny Gregory, creator of visual art