Mistake on the French

I am not very good at remembering opening move sequence and I actually don't think this is how you develop your chess. I recently played an over-the-board tournament andlearnt at my expenses how the wrong move can actually turn back against you

Here I played with White and my opponent went for the French opening. Instead of pushing or taking with the e pawn, i went for an alternative approach that my opponent was quick to leverage.

LEARNING: also opening move sequence per se is not the way to learn opening, one should not overlook how the oponent can take advantage of your own move to win tempos.