Things the US could learn from other countries

Every time I travel internationally, I notice some things that other countries do better than we do that just make sense. Here's a few of them.

Credit cards - Standardized PIN pads

In Australia and New Zealand, all PIN pads have the same layout of buttons and the sequence is always the same. Swipe/insert card, press button for payment type (cheque/savings/credit), then enter PIN or press OK. Additionally, they can use a PIN for credit card transactions which is quite convenient. US credit cards do not support this feature and require a signature.

Cash

Additionally, cash is much easier to deal with in Australia and New Zealand, for several reasons:

1. include sales tax in advertised price - this leads to round number pricing on most items. It is very common for prices to be whole dollar amounts.
2. no pennies - this one is a no brainer. Just round everything off to the nearest 5 cents (or 10 cents in NZ). Because of reason one above, this is often not even necessary.
3. 50 cent pieces and 20 cent pieces - this reduces the number of coins you need to make change for a dollar. In NZ you only need 4 coins max - a 50, two 20s, and a 10. In Australia it's 6 coins - a 50, a 20, two 10s, and two 5s. In the US you need 11 coins - three quarters, a dime, two nickels, and 5 pennies. Almost half the coins in that scenario are pennies. Update: if you remove the constraint that the total be exactly a dollar you can do it with 10 coins: 3 quarters, 2 dimes, a nickel, and 4 pennies. That's $1.04 total.
4. Dollar and two dollar coins - we have dollar coins and two dollar bills in the US but they aren't really used much for some reason. This is silly because we end up having to replace one dollar bills often due to wear. Coins last much longer than bills. Additionally, the two dollar coin allows you to make change for a 5 with just three coins - a one dollar and a pair of twos.
5. 50 dollar bills - when you withdraw cash from an ATM in Australia or New Zealand, some or all of it comes in 50s. Any business will commonly make change for a 50, even for a small transaction. In NZ, you get a mix of 20s and 50s from the ATM. When dealing with $300 it is really nice to have less bills - six/nine instead of 15 in the US.
6. Plastic money - leave it in a pocket and send it through the wash - no worries.
7. Different color for each denomination - we are moving this direction with the new versions of bills but in other countries each bill is fully a different color rather than just green tinted with some accent. Makes it easier to distinguish and sort bills.

Metric system
I can understand the barriers to change on this, but the metric system makes so much more sense. It seems to be intelligently designed rather than random or haphazard iike the Imperial/statute/whatever system that we have.

In addition to making things hard on ourselves dealing with unit conversions, we have to adjust to metric when traveling.

Not to mention our low performance in science education and trade deficits with the rest of the world... I have to think that switching to metric would at least improve our situation.