What happened was something like this, or at least this was how it seemed from where I was sitting.
It was a weekend night, we were all in a relaxed mood, just hanging out and playing songs and chatting and maybe sometimes dancing a little bit if we felt like it. You were slowly getting in to a snit because the music being played was not exactly what you wanted to listen to, and you grumbled that it wasn’t making you feel like dancing, but you wouldn’t just come out and criticise the choice of music directly, or suggest an alternative. There wasn’t anything formal about it – anyone was free to put on some music, but it seemed that you were waiting for an invitation to make a selection, and eventually everyone twigged and they kindly asked if you would like to put something on, so you did. The music you had chosen started, and that should have been the end of it, but then everyone assumed it would be ok to talk and the song would just be happening in the background. Halfway through the song you threw a bit of a tantrum and we had to go back to the start. This time everyone listened and some even got up and made a game attempt at dancing, though dancing to the track you had chosen was not easy, or possible. No one dared say a word.
A little later you accosted me as I was leaving the kitchen having retrieved another drink from the fridge. You were heading in to the kitchen to fetch a drink of your own, though I suspected you had really come in to the kitchen for the sole purpose of talking to me. You grabbed my arm. I could tell that you hadn’t actually thought what you wanted to say – you didn’t seem to have formulated your complaint before it came out of your mouth.
Anyway, you didn’t need to say anything – I already knew that your real complaint was that I was reasonably happy whilst you were unreasonably unhappy. Whatever it was, whether it really was the short episode with the music, or maybe something else had happened to make you feel unhappy before that. In the moment, you cannot acknowledge that whatever is making you unhappy should not necessarily impact on my own mood. Meanwhile, your mood doesn’t have an impact on me until you confront me with your complaint and make me realise how unhappy you are.
When we are both happy, this makes us happy. When we are both sad, this is fine too – though we are sad, we are now also happy because we can sympathise with one another.
The problem occurs when one of us is happy and the other is sad. Whichever one of us is happy cannot be happy whilst the other is sad, and whichever one is sad can only feel more sad that the other is happy.