I'm not recognised that often but I'd say once every couple of weeks somebody sticks their thumb up and goes, "Thank you very much. Thanks for the laughs." So that's good.

People within comedy just need to say my first name and they know who it is. I kind of like that. Shorthand. My friends call me Arm, which I've never really thought of as being strange until we were at a dinner party and one of the people there only had one arm. At the end I realised that all evening he'd heard people going, "Arm… Arm… Arm… Arm…"

I went through school thinking, "They'll find me out. I can't believe they haven't found me out yet." It was the same when I was a radio producer and then a TV producer. I used to fret and be very anxious. Then, when I was about 33, 34, I suddenly stopped being anxious and I don't know why other than the revelation that it's just not going to help. So don't worry.

Steve Coogan always jokes about how tacky my cars are. I remember him saying to me, "If you're not going to buy yourself a sports car then get a bog-standard family Mercedes-Benz because then at least people know where you're coming from." I'm just not interested. The only things I have a weakness for are books and music.

The big change comes when you have a family because that's when you rethink your priorities. Until it happens to them, a lot of people are worried that it will destroy their lives — and their social life — but it just allows you to start afresh with how you approach things because you have to.

Mozart's taken a long while to get into. Some bits I still find a bit twee. People within the classical music community have taken umbrage at that. I've got a book on classical music about to come out. It's a collection of stuff that I've written over the last 15 years. There hasn't been human excrement through the letterbox but, you know, metaphorically there has.

At the risk of sounding pretentious, I find coming up with the concept of God is too easy an explanation for what should stay as a mystery, really. I think God is a very human concept, isn't it? We have to explain the universe by coming up with a person — or a personality — and actually I think there's something fascinating and mysterious about the fact that it just is.

When I first started working in radio, there was a seasoned producer who said, "If you've got the right cast then you've done 90 per cent of the work." That's true.

I grew up in Glasgow. My father did a bit of everything. He was born in Naples, left in 1950. He was a salesman for coffee machines. He was a joiner; Peter Capaldi's parents' kitchen was done by my dad. With two colleagues, he ran a pizza factory. He died just as I was about to go to university, but he knew that I'd got a place at Oxford. Education was his big thing.

When you lose your temper you become absurd and you look like an idiot.

I was quite religious when I was younger. I thought, "I'm going to read the Bible. I'll do a chapter a day." About 200 pages in it was grim. It was a whole catalogue of smiting, and the numbers who were slaughtered, and just revelling in that. That was the point when I stopped. I just thought, "This isn't for me."

How would I like to be more like Alan Partridge? He lacks self-awareness, which can be a good thing sometimes. People have too much self-awareness. I'm not a great conversationalist and what Alan's got is that ability to just keep talking. I envy people who have that ability to have a conversation from the word go.

I do switch off when I'm at home. You just learn that even if it's a really pressing problem the film isn't suddenly going to disappear or the TV show isn't going to get cancelled overnight. You can deal with it the next day.

I'm funny with my friends but I don't feel the need to perform in strange company. It's not important to me today that you are amused.

The thing that really annoys me is when people go, "I know you're terribly busy but I'm wondering if you could do this?" Don't for one second think that by acknowledging it that somehow buys you an exemption, but people do. You know, "I know you don't like stabbing but do you mind if I stab you?" As if somehow that's fine because you've said. I don't get that.

You've got to allow yourself the possibility of failing. If you start becoming cautious you will get a bit bored and people will notice that you're just treading water. So you have to try new stuff that will push you. It might work or it might not work. You just have to go for it, really.

I have a nap at about 1.30 until 2.00. You've got to set the alarm because if you do more than 20 minutes then you're drowsy for the rest of the day. I thoroughly recommend it.

My vice is probably that I'm quite boring. I enjoy dossing at home with the kids. I like meeting up with friends for dinner and chatting. I'm not one for having lots of hobbies.

I used to run but my knees are absolutely fucked. I was a good runner at school, good rower, too. I didn't row at university because you had to get up at 5am. I didn't like the idea of getting to sleep at 4am and somebody knocking on your door an hour later. But I enjoyed it at school. We rowed on the Clyde. The person who ran our boathouse was also the guy who fishes bodies out of the river.

Why do I think we're here? There's no reason. That's kind of exciting because it puts the pressure back on you to come up with a reason.

When something is so funny it makes you laugh, you just feel better.

The Death of Stalin, written and directed by Armando Iannucci, is out now.