Driving lessons

I spent one of the afternoons when I ill with the flu watching a rather quirky British film called "Driving Lessons". I thought the film a bit odd when I had an elevated temperature, and watching it a second time when feeling more normal only confirmed my original suspicions. Maybe the best thing about the film is that includes a Richard Thompson song in the soundtrack ("One door opens") and an obligatory (these days) Nick Drake song (part of "Pink Moon"). 

Thinking about the film later, many questions popped into my mind, mainly about the characters' motivations:

• How could Ben (Rupert Grint) be so gauche at the age of 17?
• Why was Laura Linney - an American - cast in such a quintessential British film? How could her character - a vicar's wife - have no qualms about committing adultery with the parish's junior priest? And even worse, how could she do it whilst leaving her son in the car outside, whilst ostensibly giving him an eponymous driving lesson?
• When was Evie (Julie Walters giving a fantastic performance) lying and when was she telling the truth? Was she really a Dame? Was she really suffering from cancer (presumably not, as she denied that one herself)? How did she manage for money? When she and Ben went camping, Ben had to pay for the campsite. The next minute, they have driven from somewhere (presumably near London) to Edinburgh, showing no signs of tiredness. Who paid for the petrol on the way? If presumably they had money, so why did Evie pawn a ring in order to give Ben money "to buy a clean shirt". How did she pay the hotel bill for her drinks and Ben's room?
• What was Bryony's motivation in seducing Ben? Did she sleep with every boy that she met? The entire Bryony episode seems in retrospect designed solely to give Ben a reason not to accompany Evie to the poetry reading.
• How could Sarah be so stupid to say what she did to Ben at the end of the film? Every son wants to hear about his mother's infidelity...... I thought that maybe she would empathise with him, but she appeared to be still under his mother's spell.

I find my reaction to this film interesting because I was able to find so many things unexplicable within the film, and yet I enjoyed it. I later watched a film called 'Smother' (with Diane Keaton) which coincidentally has a similar theme, about a son trying to build his own life apart from a domineering mother. No doubt this film had a budget much bigger than that of 'Driving lessons', and in my opinion it was much worse, by about the same factor. But why? Because it's an American film? Because it got on my nerves? 

British films tend to be much more realistic, featuring people who could easily have lived next door to me when I lived in Britain (at this moment, I will note that Dr David Owen, at the time Britain's Foreign Secretary, lived about three houses away from me when I lived in London). American films tend to populate some kind of fantasy world, and one could never imagine Diane Keaton living next door (as much I would like to) or even her son, Noah.