Tim Key: It's OK to share a sofa with a stranger in a juice bar. Isn't it?

(Ping Zhu)

I'm sat on a sofa in a juice bar. I'm sat next to a girl with long, radish-red hair and we're both typing away. God knows what she's typing – she keeps angling her laptop screen away from me. For my part, I am typing a column about personal space. My theme came to mind for a couple of reasons: firstly, she has muttered the phrase approximately four times since I've joined her on the sofa. And secondly, in related news, because I am paranoid that I might have invaded hers.

Apart from me and her, this place is pretty much deserted. I came up the stairs with my Carrot Energiser and surveyed the joint and, judging by the level of her juice, I imagine she must have done the self-same thing maybe 20 minutes before me; she still has a third of a pint of vile, dark-green, healthy-looking liquid in front of her. I imagine she and I had a very similar bunch of thoughts before hitting the sofa.

Everywhere you look in this place there are hard, wooden chairs. Unforgiving, unyielding seats that make you wanna churn. Grim, really. And then there's this sofa. Leather, oxblood in hew, stuffed away in the corner. It's a no-brainer. I imagine everyone who emerges into this room does the same thing: makes a beeline for it. I did. I waddled over, popped my juice down, asked her to budge up, and took the weight off. And more or less directly after that she emitted her first huff.

When it comes to sofas, I have never been a huge worrier about 'joining the incumbent'. They're designed to be shared by a minimum of two people, so anyone flying solo should know that they're fair game. It's the same principle as park benches and, in my opinion, dodgems. You can always be the first to sit down on one of these things, but you have no right to expect to be the last. Recently, I stayed at a friend's flat after a night out in Waterloo and was asked to sleep on the floor even though he was utilising a double bed ALONE. After maybe 90 minutes of discussions, he yielded half the mattress and I slept like a baby.

Radish is still sniffing and snorting. I just caught a look at her screen. A lot of Facebook going on there. A lot of 'refresh'. Occasionally she gathers up enough willpower to make minor inroads into what, I assume, is her main project. She seems to be writing some kind of screenplay. One of the characters appears to be Japanese. I can't get a firm idea of whether it will be any good or not. It looks like the protagonist is riding an elephant. I think it'll cost a bomb to get made, if it ever does. Occasionally I look across at her, trying to psychically transmit my reservations to her. She stares coldly at the other seats in the juice bar. She is trying to psychically communicate "All these chairs and you choose this one". I now cast my eyes round the room. I am trying to silently say "Yes, it's because, like you, I like to be comfortable".

I glug some more juice. I've been here 25 minutes. I'll be pleased to polish off this paragraph and get out of here. I have started to say "What?" every time she sighs and it's doing nothing for the atmosphere. An old lady comes in and I will her to come and sit between us. Show this madam that it's not me that's got the problem, it's her. But the old lady has sat on one of the rock-hard chairs. It almost looks painful.

I've just caught another glimpse of her screen. Script's taken a back seat again; she's compiling a Facebook status update and I'm heavily involved. She's called me chubby. I feel like it's a sign for me to leave.

I gesture to the old lady that I'm off. I tell her how comfy the sofa is. I really sell it to her. She doesn't want a scene so she's coming over. Another sigh from Radish, and that's me. Juiced and rested. Back into the field.