Usually on "Monk" (a show I love), the crime-detective aspects are pretty far-fetched (full of plot holes), but you appreciate the show for the acting, humor and lovingly established characters. Things are somewhat reversed in this episode. The crime was clever and logical, though it could have been presented better -- but it was OK. What disturbed me is the major premise here. I usually have to "willingly suspend disbelief" to enjoy an episode. Here it was impossible. Throughout the episode Natalie was apologizing for letting a thief steal a bicycle and she was pressuring Monk to solve the case/find the bike, and Monk takes advantage of her guilt by berating her (unfairly) constantly. Monk's berating her and her self-recriminations were repulsive, endless and mostly unfunny. I'd be rich if I had a nickel for every time Natalie said "I'm sorry." First of all, Natalie didn't do anything to be sorry for. No one in the world would blame her for assisting the biker (who had stolen the bike) who fell from the bike. Natalie wasn't conned; no one was chasing the biker. Second, Natalie had no reason to promise the real owner of the bike that she would recover the bike. The bike wasn't worth much, had little to no sentimental value, and the owner was apparently a successful, upper-middle class or wealthy scientist-businessman, who wasn't much upset about the bike being stolen. Third, it was incredible to see Natalie give up so much for Monk to take the case -- in effect she told Monk that his taking the silly case would make up for the all the insults, exertions, inconveniences, etc. she ever put up with working for him! Wow!
Let me note that there have been many times where it was cute/funny to see Monk's selfish, sardonic nature -- situations where there was some benefit to Monk and no real harm to anyone. In this episode it was just mean, crazy and potentially harmful for Monk, for example, to go into a fit because Natalie "deserted" him (he had stepped onto something that may have soiled the sole of his shoe) to administer aid to the biker who had careened off his bike and there was no one else around to aid him. Lately they make Monk into a mean jerk. I don't like that.
There was some humor, but not enough. The scene where Monk rolled down an incline in a wheelchair and crashed was hilarious, though.