I try not to have too many regrets. I just do not have the energy to dwell on what I shouldn't have done or should have done in my life.
But, there is one thing I do regret.
Not learning to play an instrument. I wanted to learn to play the clarinet in fourth grade, but never did pursue it. I learned to play a few songs on the piano, but never took any serious lessons.
I would have loved to know how to play, but just never learned.