Question: If Monk is afraid of germs, then why does he keep touching things that could possibly have germs on them like parking meters or books?
Answer: That's the thing about Obsessive Compulsive Disorder. It's not something rational. He just has to touch things like that. It's not something he can rationally think through. However, since part of his disorder includes an obsession with cleanliness, he also has an assistant walk around handing him wipes periodically. It's like when he gets a cold and uses both a humidifier (because that's what you use when you're congested) and a dehumidifier (to counteract the effects of the humidifier). He may spout rationalizations after he does something, but his compulsions exist outside of any rational thought whatever.
Question: In the last few episodes of series 1, Horatio tells a few people that they will be spending the next few years a jail. But sometimes he says a 6x6 cell and others a 6x9 cell. So I was wondering do the sizes of cells usually differ or was it just a slip of the tongue?
Answer: Yes, sizes of jails differ.
Question: Why does Foyle wear an overcoat at all times of the year? I know that the English summer is temperate, but always a long, floppy overcoat?
Answer: He doesn't actually wear it all the time even in summer. In some episodes in the summer he simply wears his suit with jacket.
Question: What does ISD stand for in Baltimore police? It is mentioned by major Colvin to Carv after police officers correctly guess that somebody (Carv) has moved the dead body (Internal affairs is called IID during the show). It is mentioned again in Season 4 episode 8, when Herc worries about how to get back an expensive camera that Carv helped borrow to that ISD department.
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.