Things that haven't gone to plan.

Incredibly lush growth.
Thinned out at the right time.
Grown for the right amount of time.
Carrot tops appeared to be about the right size.

BUT

The pot was obviously not deep enough........

Planted as a seedling.
Quickly took off and was starting to overrun the adjacent parsley and chives.

BUT

Died off substantially following a light pruning and never recovered.