@idiotsecant is correct. Length of arc correlates to voltage, while most of the potential pain or damage from an arc will correlate more to amperage and/or to duration.

You're correct, but just for fun's sake:

The amperage of static elecricity discharges like this can be quite high, tens of amps is common.

So walking across a carpet and getting a shock can easily be tens of amps at thousands of volts, and we're just totally fine (because it's for a tiny fraction of a second).

So it's not the Amps that get you, but the Coulombs? Or is it the Joules?

Lethality of electricity is multi-dimensional, trying to reduce it to a single quantity does not really work (exposure time and electrical frequency are very important).

neither. even a shortcut saying like "total energy delivered" is not accurate, because it depends on how it is delivered and how it dissipates.

styropyro made a fascinating (if terrifying) video about it

Sounds a bit like fuse wire (except the frequency dependence)... There's both a current and a time component. High overloads can be tolerated for a very short time without blowing the fuse, while low overloads can be sustained for longer before the fuse reaches its maximum temperature and breaks.

It also matters where the arc lands. I leant over an electric fence (whim I thought was off) wearing wet swimming shorts to fetch a ball, once.

Never, ever again.

You had less voltage, but whole lots more current than parent post.