Am I a good listener
My wife asks me to do something, so I do it, but then it isn’t what she wanted. Is it that I don’t understand?  Or am I not a good listener?

Listening is a skill that requires cultivation.  Sometimes 2 people hear the same thing but think it means different things.  Before you act, to help avoid misinterpreting, check in with your spouse to make sure you heard correctly...here's how:

Rephrase what you think you heard.  Make sure your tone of voice isn't defensive, your expression shows interest, and your body language is open.  Then ask if that's right, and hopefully the answer is yes!  If it isn't, keep summarizing until you get that "yes".  When you're sure you understand your spouse, then you can act accordingly, on accurate information instead of your (mis-)interpretation.