It makes me want to smoke.
I think I mentioned once here that my rate of smoking is about one cigarette every 8 years. That means I'm due. And since I'm in London alone, away from husband & sister for the next day, I can run riot and have that wild cigarette... I probably won't. Sigh.
Before she left for soggy New England, my sister and I were discussing the reason for our difficulty with the change. The obvious difference is the coinage for small amounts; one and two pound coins. The US has a dollar coin, but you only ever see it when you use the stamp machines at the post office and get change. So, any amount under $10 gets paid for with coins in the UK. But that is easy to adapt to. Where we're having the hard time is counting change under 1 pound.
The #1 reason: no 25-pence coin. Units are 1, 5, 10, 20, 50. The typical handful of US change contains these units: 1, 5, 10, 25. Half-dollars exist, but are rare. I have a lifetime of change-parsing habits centered around the quarter as the most important coin. The handful of change in my pocket right now does not include an equivalent. So I'm at sea and count slowly.
The #2 reason: the coin in the size that my brain has been trained to parse as "dime" is actually the 5-pence coin.