I had a fight with my bridge partner. We were defending 5H doubled, Ian led a spade which I won. I returned a spade. If I had switched to a diamond we would have defeated the contract. 

We didn't say anything to each other at the table. The fight came later.

After the match I said 'sorry, Ian, I should have switched to a diamond.'

'No, no, it's my fault' he said, 'I should have led a diamond in the first place.'

'No, no, it's may fault' I said. 'There's no way you knew to lead a diamond, I definitely should have switched'.

That went on for a while.

That's a big deal. To have a partner who supports, encourages, doesn't try to make you feel bad when you make a mistake is a wonderful thing.