if were showing the fuel station pump clerk that the bottled water you had brought in was something you didnt need to purchase..and btw, had the top off and threw water all over their credit card machine..how most would react and what if customer said.. Dam sorry,,if you have towel i will wipe it up"…? and why?..
how would differ this situation maybe in Britain from USA? and why?

I work behind a till (not at a petrol station, no difference!) and if someone accidentally spilled something on my till or over the atm I wouldn’t really care. I’d just wipe it off. Not like they threw it on me on purpose.

I guess your person was having a bad day – I was working yesterday, there is no extra pay for people who work on Easter Sunday! Puts some people in a really bad mood.