Charms of the Phoenix

Not necessarily the most efficient or effective things, or always those I would actually choose, but those I find attractive.

Most charming
Encryption:
One time random pad.
Two colors:
Black and green
Ways to kill people:
"Squish". Poison and disease work sometimes, stabbing can create shock, but when faced with an unknown lifeform the more reliable thing is to beat it into little itty bitty bits. There should be a good quote here sometime.
Ways to kill things in or with large gravity wells:
Drop rocks down the gravity well. Duh.
Ways to kill things without large gravity wells:
Continuous beam terawatt laser! I don't know exactly how effective this would be. You have to specify the intensity, of course, and I don't know what range it's good for. But since humanity is estimated to directly use 2 terawatts of power at the moment a warship with a teralaser cannon would be firing a gun comparable to all human civilization. That's charming.
Space drive:
Orion. "PUTT...PUTT...PUTT..."
Historical periods:
The Enlightenment; also the time of the Ionian philosophers.
Measuring systems
The English and U.S. customary system. I like a unit of mass called a "slug".
Philosophers:
Democritus.
Insect:
The Monarch butterfly. It's common, it gets around, and it makes itself poisonous by gorging on milkweed.
In general though I don't really think of insects as charming. I can understand why one might, but personally when I think insect I think "squish". They can perform their vital ecological services away from my nose thank you. That's why we build paved cities.
Currencies:
Barley. I think the Babylonians used this. Money that's worth something! Either bread or beer.
Niven's Roentgen Standard for using radioactives as money. "Hot money" indeed. The essay is in Limits.
Females:
Sociopolitical concepts:
Privacy. Also honor.
CS concepts:
Recursion.
Quark:
Strange
Numbers:
Any prime quatrain, a la 11, 13, 17, 19

Back to me.