Spring, Oxford, 2010. Sitting on the balcony of my local pub. I’d been here many times before: I’d lost a ring through the wooden slats to the water below, kissed the first person I loved here, argued with the first person I loved here, and cemented it all with wine.

My friends and I had pooled our conversation with the table adjacent and we had come to a seat sharing arrangement. Rizla papers were swapped, names exchanged and introductions made. Forget Paris, Oxford in the spring is beautiful. To our right, a man in a suit sat by himself, smoking. I asked him to join our new milieu. He said he felt like he was intruding. We’re all intruding, I said, only half of us know each other.

Chris – I’ll call him Chris – was in town for his daughter’s graduation ceremony. He lived in Dubai, and had flown over specially. The ceremony was why he was wearing a suit on a hot May day. Did I also go to Oxford university? No, I said.

Pause. Well, I had an interview, I said. Didn’t get in. Does that bother you? Chris asked. No, I lied. Or maybe I didn’t lie. I wasn’t sure. You must be very proud of your daughter. Chris said he was, but he would be proud of his daughter whether or not she had gone to Oxford. He bought drinks for the assembled crowd – about 15 of us.

I was studying at the time at a further education college, which is where I had met the person I had fallen in love with. I had moved back from a period of living in Russia. I was 20. I had applied to Oxford on a whim, without A-levels. I had just been diagnosed, not for the first time, with bipolar disorder. (These things aren’t exactly clear cut). I had begun new medication, which made my head cloud over like a pint of cider and most things terrified me. I often felt I was slipping through the slats into the water below.

What was then the Duke’s Cut pub in Oxford, 2010. Photograph: Hannah Jane Parkinson

When Chris returned from the bar he asked me what I wanted to do in life. I said I no more knew how to answer that question than I knew what I wanted to eat for dinner that night. Perhaps that was part of the problem. I want to write, I guess, I said, but I was aware of how poncey that sounded. A lot less than some of the things he had just heard at his daughter’s graduation ceremony, he replied. We turned our chairs perpendicular.

Who was the woman sat next to me? Oh, she is the woman I am in love with. She loves me too, and I am sure of that, I said, but it was, to coin a Facebook status, complicated. Sometimes she makes me feel like I am made of platinum and other times of papier-mache.

There’s a reason Tennessee Williams wrote about the kindness of strangers

At no point did Chris say: phwoar! Two women. Or, can I join in? Or, hmm, you’re too pretty to be a lesbian. Or, what is the sex like? At no point did Chris, in his mid-40s, put his hand on my thigh. Or suggest we go on somewhere. At no point did I learn the location of Chris’s hotel.

Instead, he told me about his work in Dubai as an accountant, and how he didn’t really enjoy it. Chris was adamant that I shouldn’t end up as an accountant in Dubai – not much of a worry there, to be honest, Chris. No, but Chris, said, listen to me. And we weren’t even that drunk at this point. You can do anything you want to in life.

That is very nice of you to say, I said. Chris told me to stop being facetious. He said that he thought I was smart and funny and kind and clearly driven and that he would put money on me doing anything I wanted in life. Fuck Oxford, fuck however I got where I wanted to go, but he was certain I would get there.

I said maybe I had thought that once, but not since … and then I told him about the bipolar. And the word shifted in my mouth when I said it, because it was still an alien part of language to me. I fully expected Chris to throw himself in the canal. But instead he said: “Well that sucks. That’s awful.” And I was glad he had said that because I thought that too. But, he said, now I just have even more respect for you. “You don’t think I’m crazy?” I asked. “Sure, I think you’re crazy.”

There’s a reason Tennessee Williams wrote about the kindness of strangers; there’s a reason the phrase has entered the cultural lexicon. The kindness of strangers can turn a bad day good, or give hope, or change lives, or more banally, make sure we’re not late to something, give our legs a rest on the bus home. I try to be kind to strangers. Strangers are kind to me. In north London a few weeks ago, a man handed me a piece of paper with a smile on it; a woman let me use her phone, in the rain, entirely lost.

In the bar, I spent about three minutes in the loos trying to get it together because Chris had sketched out the sort of faith I should have had in myself. Because Chris, wanting nothing in return, and only mildly tipsy, had told me I was worth something. At one point, I mentioned that despite loving the people I lived with at college halls, I thought it might be good to move out and have some space. Chris offered to help me out with money. Absolutely not, I said. Who accepts money from strangers in bars? He’d just spend it on worthless things otherwise. You can pay me it back when your first book is published. I told him to stop being facetious.

An hour or so later, Chris got up to leave. He had dinner with his daughter and her friends to get to. We had the kind of emotional farewell that is usually reserved for airport scenes in films. The person I was in love with glared at me. Chris told me to take care of myself and remember everything he had said.

When, later in the evening, the light slid behind the buildings and the temperature dropped, the rest of us gathered our own things. Slipping my phone in my pocket, among keys and a lighter and a week’s worth of receipts, I felt something else: $1,000, in cash. He hadn’t even let me buy him a drink.