I found this show a bizzare mix of genres that somehow worked. Derek is such an authentic kind person - but so hysterically funny without trying. It also highlights the forgotten - the elderly and their dignity and its hard not to be in awe of the characters that dedicate their life to caring for them.
It was slightly politicised in some areas - such as Hannah's plug for assisted dying, which I thought was a shame, as it didn't really fit the narrative and tone of the show.
Also- Kev's character was just too much. The constant sexual innuendo was just revolting and didn't fit well at all with Derek's child like naievity. I think Kev is an important character as it shows how Derek's acceptance of all types of people led to his redemption, but the way the show allowed Kev to carry on basically was really poor taste and made some scenes too hard to watch. Its a shame to see good TV ruined like this - its just not necessary and it adds nothing to the comedic or artistic quality.
I thought the reconciliation between Derek and his father, whilst perhaps a little unrealistic in real life, was a nice touch and fitted well with the character. The message by Derek after his fathers death, about not leaving things unresolved in life, was very powerful. I found it very touching - I lost a friend recently, who I hadn't contacted for several years. I found several themes throughout the series very human and cut through like that, even though I laughed through most episodes.