at the bar vs on the bar

at the bar or on the bar, where I live people prefer to use the latter one. It doesn’t make sense to me because if I say I’m working on the bar that means literally I’m standing on the bar that makes me laugh. That would be more logical to me If I said I’m working at the bar, what means I’m working around the bar.

is there any language coach who would help to put it straight as I’m totally confused now, regarding it.

Thanks in advance!

You stand/work/order at the bar.
The drink is place on the bar.

I think the same, but why do people using ‘on the bar’?!

Do you work in a hotel or similar? That would explain it.
“I’m on the bar tonight.” which is an informal way of saying I’m on the rota to work at the bar.

Yes I’m working in a pub, and allways my colleagues say it, I’ve got used to say it as I picked it up. Unfortunately

No worries as long as you always use it informally.