Yes, you and your rules of ten, I always have to multiply and divide things to figure out what's going on. I actually find arbitrary points of comparison easy to remember. Plus 60 miles an hour is a mile a minute. If your speedometer beaks and your on a freeway (other than California which doesn't have mile markers), you can try to go 1 mile a minute and be around the speed level. That's what 100 KM an hour? So I either have to count 40% more KM markers (over mile markers) in which case I'd lose count because I need to keep track what the time is or some how know that 100 KM/hr is 1.66 KM every minute. In this case I would have to estimate 2/3 of a KM which can lead to lots of errors if it's a long road trip.

I have a British truck, it breaks very often so you need to know how to time/speed distance yourself.

EDIT: Try losing weight in terms on KG to pounds, it makes weight loss or weight gain seem VERY slow. The last thing the US needs is weight gain to seem slow. What do you want to hear, you weight 500 lbs or 227 kilograms?