Late to the party on this thread. U.S. born and raised, accustomed to Imperial Units but learned metric in elementary, and used it extensively in college (called Systems International there). Personal view:
1.) Metric is great if you want to convert units, such as Kg to grams to milligrams, etc...
2.) Most Americans in daily life don't do that much. One might know how many feet are in a mile, but it's rare in practical daily life we need to know or use that. Teaspoons to tablespoons is the main conversion in many people's lives, I think, and we don't do that often. Pints to gallons very rarely. We could argue acres to hectares, but I think few regular folks use hectares.
3.) Once a system is entrenched, it's very hard to pull out and replace. I have an intuitive grasp of Imperial Units, and to do Metric I do rough conversions. If you tell me any measure in Metric, you can bet I'm internally running it by this mental cheat sheet:
1.) 30 cm = 1 foot (2.54 cm = 1 inch).
2.) 10 m = 33 feet (thank you, scuba diving).
3.) 1 km = 0.6 miles.
4.) 1 kg = 2.2 pounds.
5.) A liter is a little more than a quart.
6.) Celsius degrees are 'bigger' than Fahrenheit degrees; 0 = freezing, 100 = boiling, 28 C = 82 F, somewhere in the 20-25 C range is around room temperature with 20 being chilly.
That said, we do have some metric use, mainly 2-L soda bottles, and syringes with 'CC's' (cubic centimeters or millimeters). Some tools are in metric.
Despite having used the metric system extensively, I wasn't raised in it and didn't make real world associations (e.g.: distance to a nearby grocery store, predicted temp. on a hot day) with it, so I have to mentally convert to Imperial to understand the significance of a metric measure.
All that said, many in other nations don't seem to see any hypocrisy in non-10's-based time measurement. We can't get around 365 1/4 days/year, but we could divide the day into 10 longer hours, make our weeks day days and months 10 weeks, yes? We could have 1 day = 10 hours, 1 hour = 10 minutes, 1 min. = 10 seconds, etc...
But nobody bothers or thinks much about it. They're content with what they know and it works for them.