How come it takes some artists longer to paint than others?

I wanna learn how to paint fast too. Is there a method or techniques that can help with this?

Background: I was on vacation last summer and I had a self portrait done. He was someone on the street who paints you. He turned me into a cartoon furry on a beach pier. It only took him like 5 to 10ish minutes to finish painting me. It was truly impressive. I don't paint often but when I do it takes me like an entire afternoon to finish something lol