'So you're walking home from the rehearsal dinner? Along these winding, pitch black Sardinian roads?'

'Yeah. It's Shabbat.'

'But what happens if you don't walk home and take a cab? Do you get punished? Can you commandeer a horse?'

'It's tradition to walk.'

'But there's no punishment if you don't?'

His plan was apparently to leap into the air, roll off the bonnet and land

My boyfriend was asking awkward questions again.

He had just come from another wedding where a Roman Catholic monk had given the sermon, which had been so powerful it had led one of his friends to have some sort of existential crisis, and was thus in an inquisitive mood. He likes his faith straight up - with a dash of hell fire.

I knew 'It's tradition' was simply not going to cut it. He wanted to know what happens if Jews get a cab on Shabbat, or eat pork, or break other laws - did they go to hell?

Was there a Jewish hell, or at least limbo? If there wasn't a hell, what were the incentives for being a good Jew? Why did some people eat pork and not others? What was all this picking and choosing which Jewish laws to follow and which to ignore about? Why was it all so arbitrary? He just didn't get it.

None of my Jewish friends had been able to answer any of these questions coherently, or even agreed with each other beyond 'it's tradition' - which had always struck me as a bit of a cop out.

Luckily, we arrived at the venue and the conversation was abandoned, much to his disappointment. He'd just have to wait until I found him a patient rabbi to quiz back in London.

The next morning at breakfast, we discovered our night walking friend was sporting a crutch. He'd managed to sprain his ankle whilst walking back to the hotel in the dead of night - something about enacting what he'd do if a car came along and he needed to avoid it.

His plan was apparently to leap into the air, roll off the bonnet and land on the other side unharmed - but when he'd practiced his leap, he'd somehow managed to miss-time it (one too many limoncellos?) and taken a tumble.

If only he'd taken a taxi.

Later that afternoon, as he gave a reading from Genesis on crutches, at the beautiful non-religious wedding ceremony, it struck me that perhaps 'it's tradition' isn't a cop out after all, and was as good an answer as my boyfriend was going to get. After all, tradition, like any form of idiosyncratic behaviour, is simply a way of establishing a sense of shared identity - a sense of the familiar when in unfamiliar territory, even in the dead of night in the middle of nowhere in Sardinia.

There doesn't have to be a logical or legalistic explanation beyond that: an emotional response toward a feeling of comfort is enough.

And, failing comfort, the righteous pain of a twisted ankle in pursuit of tradition will do…