Isn't it a bit unnerving that doctors call what they do "practice?"?

Great George Carlin joke there. Seriously though the doctor is a "practitioner" and according to the verb "practice" has one definition which is "habitual or customary performance; operation". Since most medical problems are common a doctor will typically use the same or similar specific treatment for each problem multiple times. Also, according to "practice" comes from the late Middle English word "practise" meaning "practical application".