My garage door makes a jerking motion as it opens

I messaged my friend and asked him to send me the number of the man that fixed his gate. My friend sent me the number and I phone right away. “Hi, my garage door isn’t working properly, could you please see if you could fix it?” The man responded: “Sorry, I can’t help you with that… I’m a podiatrist.” “I know,” I responded, “but I figured that if you could fix my friend’s awkward pigeon-toed gait, you could fix my garage door, too!”