I can only do one thing with my left hand: write. For whatever reason, I learned how to write, draw, and other pencil-work with my left hand. I've tried and tried to become proficient with my right hand in regards to writing, but it just hasn't and won't work! I told myself it's because of muscle memory, but for 12 years it hasn't worked! D:
With everything else, I'm a right handed guy. I stab meat with my right hand, I cut with my right, eat with the right, drink...etc. I wish I could be ambidextrous though!