I was on the tube a few days ago, and I realised I looked like a tosser. I had sunglasses on, underground. I am pretty sure that is unacceptable, but I had forgotten I was wearing them. However, in order to take them off, I would have had to find my other glasses, or I wouldn’t be able to see. These were in my bag which was on my back, so I would have to take my bag off and... long story short, I decided I would rather some people between Green Park and Leicester Square thought I was a tosser than go through the ball ache of rummaging through my bag on a crowded train.

Given all this, I find myself hugely impressed by people on public transport who couldn’t give a shiny shit about what people think of them. I recently saw a man on a train platform dancing animatedly to the music blaring from his phone. There was nobody standing anywhere near him; everyone else had assumed an insanity blast zone and kept their distance, lest it was contagious and led to a version of Bird Box in which everyone felt compelled to maniacally throw shapes to Sean Paul’s first album.

I was struck by the fact that this man seemed easily the happiest person on the platform, and I had one of those Sex And The City epiphanies: “When you think about it, maybe we’re crazy and he’s the sane one”, or something like that. And I resolved to be less judgmental.

This lasted all of one week, when I was approached by a man while waiting for a train. He looked slightly wild, and I was aware of him looking at me for a while before deciding to approach. “You’re Romesh,” he said.

I confirmed this, and he went on very politely if a little overexuberantly, to give me a rundown of what he thought of my work. So far so good: I felt that I was learning something. I was having a conversation with a stranger on public transport and there had been no casualties.

It was at this point that something incredible happened. As he was talking, his exuberance led to him shooting a small piece of spit directly on to my cheek. This is obviously not ideal. He knows it’s happened. I know it’s happened. If you’re with friends and this happens, you do a little embarrassed laugh and say, “I spat on you! Oh God, sorry”, and it’s forgotten about. But we were strangers. What do you do in that situation? Here’s what I think you do: you pretend it never happened. You both carry on talking, both knowing but never acknowledging the spitting incident, before saying goodbye and dealing with the mild trauma alone.

This man made the amazing and baffling decision to say, “I’ve spat on you”, and then wipe my face with his fingers. Holy shit. A minute ago, I didn’t know this man existed. Now he was gently caressing his DNA from my cheek. I decided to bring the conversation to a close by saying goodbye and walking away.

You may think I’m being harsh. You may think I am judging a man who found himself in an embarrassing situation and panicked. And this level of harshness may lead you to judge me.

But let me mediate that judgment by telling you that, during our conversation, he also informed me that he hadn’t had time to watch everything I’d done because he spends so much time “shagging women”.

I’m never talking to strangers again. Except for every day, from a stage that is not within spitting distance, as part of my job.