These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
I Knew It: Clever viewers may find themselves shouting this, especially since whodunnit is often not who you'd expect and therefore being right is all the more exciting.
Jerkass Woobie: Barbara in the pilot, "A Great Deliverance". Viewers spend most of that episode both wanting to cuddle her because she's had such a crappy life and smack her for being bitchy — at the same time. This does persist into the first series, but has largely been replaced with Jerkass Façade (plus plain old Woobie) by mid-series 2.
Relationship Writing Fumble: If the writers wanted viewers to believe Havers and Lynley aren't falling head-over-heels in love throughout the course of the show, they really shouldn't have had them call each other their reason to get up in the morning, or given them the infamous Cry into Chest at the end of "In Divine Proportion" that looks like nothing so much as a man comforting his traumatized lover. Many, many fans have pointed out that Lynley has much better chemistry - and a much healthier relationship - with Barbara than he ever did with Helen.
The Scrappy: Lesley Vickerage's Helen, who is by and large considered a whiny, selfish milquetoast. Catherine Russell's incarnation of the character is generally considered bland but likeable enough, but virtually everyone wants Emma Fielding (from the pilot) back.
Woobie: Both the lead characters, in spades. When the storyline gets sick of torturing Lynley, it takes a break to snack on Barbara. And of course, because the two are soclose, when one of them is hurting, the other is too. Luckily, the comfort and strength they find in each other helps make up for it — a little bit, at least.