Continuity mistake: They interview Jimmy Belmont in prison, who complains how Monk sent him there for killing Randy's uncle in 'Mr. Monk Visits a Farm.' However, in that episode, Monk tricked everyone (including Randy) into believing Randy had solved the murder.
Continuity mistake: At the end, when he is talking to Natalie about quitting since he has solved an even number of crimes, Monk is peeling an orange. The peeling that he is letting dangle from the orange changes from above the counter to touching the counter and back to above the the counter, depending on the shot.
Continuity mistake: The Captain hits the murderer at the end with his left hand. In the next shot of the Captain he is shaking his right hand as though that is the hand he used to hit the murderer.
Continuity mistake: The first victim's body and the floor around her are covered with pieces of glass, but the hole in the pane of glass is only about the size of a fist, not nearly big enough to leave that much glass on the ground.
Answer: Notice also that in the opening credits scene when he is touching parking meters her also wipes his hand on his clothes each time he does it.