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.
Ian Reed's skill at psychological manipulation makes it very hard to tell whether he had always secretly been spiteful and amoral, or whether he was a decent guy who was tempted by the promise of easy money, panicked and behaved like a coward when things went wrong, and then pretended to lack remorse as a way to troll Luther into putting him out of his misery.
Award Snub: Despite massive acclaim Idris Elba never won an Emmy for playing Luther despite being nominated for all three seasons. However he did get a Golden Globe, so that softens the blow a bit.
Bat Deduction: Some of Luther's detective work is arguably just guesses that happen to be right.