Planting mint by my garden beds, it grew better than anything else and
tried to take over.

Planting Lamb's Ears in the flower bed, because I thought it was
pretty. Until it tried to over-run everything else.

But the best one was my first rock wall around a tree. When I was done
and stepped back to look at it I laughed until I cried. It was the
funniest looking thing I've ever made. Then I had fun demolishing it
and started over. Third time was the charm!