As a non native speaker, this messed me up for years
I always heard about "being up" for something, so I logically assumed that being down meant the inverse. Even more that "feeling down" usually means not being able to do things.
Not to confuse you more, but with your phrasing you are correct.
If you're up for it, or being up for something, you are interested. Similarly, if you're down for something, or you'd be down for it, you are interested.
But if you are feeling down, you are not up for it.
The former 2, the verb is the action of being ready.
In the latter, the verb is feeling and down is the state.
For example, despite me feeling down I'm down to go out and party tonight.
It’s not about the crest or the trough. It’s about the motion of the ocean baby.
Up and down are both disturbed, ya dig? It means the thing made an impression on you. Got under your skin, gave you the itch, it’s bugging you, eating at you, lighting a fire under your ass, putting you in the hot seat.
No more smooth sailing. Buy the ticket, take the ride, you know? Get this idea off the ground, get up and bounce. You know, jump around.
It makes a little more sense with the context that “I’m down” is shortened slang for “I’ll throw down on that”, itself slang for “I will get in on this situation” (as in “throwing down” some money or chips when gambling)
I thought it is short for "I am putting myself down for that" or "put me down for that". As in, putting yourself down on a list for attending an event.
In the game of hell let loose you're constantly trying to build Garrison's for your team to spawn on, and destroy Garrison's so your enemy can't spawn.
Highly ambiguous
Garrison down on the point!
Does this mean a friendly Garrison was just built? Does this mean the enemy Garrison was just destroyed? Who knows! Why not both?
Flammable. Inflammable. Famous. Infamous. So many dumb prefixes that make no sense.
There really needs to be more language revisions every couple decades to get rid of stupid shit or revise letters, words, and spellings to be more in tune with their phonetic pronunciations.
They aren't dumb, peoples' usage is just poorly informed and incorrect.
Famous/infamous are not synonyms, so you shouldn't be using them interchangeably. Infamous specifically means "Famous for the wrong [read negative] reasons". Like a serial killer. Or somebody who is famous for knocking over and breaking a priceless work of art.
If something is flammable, it can be set on fire. Like wood, or paper. If something is inflammable, that's still true, but it has the additional property of being able to spontaneously combust, without being actively set alight. Like oils, or unstable chemicals, or some explosive material.
These are levels of nuance which are actually really useful, if handled correctly. The fundamental rule appears to be that in an "in..." word, the prefix gives specific detail about how the object holds the properties of the suffix.
C / K / S. Remove X. Change letter names to match their sounds.
A / ugh / Ayyy.
B = Buh
C = Removed? It's just K or S in reality.
D - Dih
E - same?
Etc. etc. there's better linguists than an old school Grammar Nazi turned Language Darwinist.
I like the idea of removing upper and lower case letters too and changing their denotation with a new symbol, but I'd have to think longer about case studies or could be easily persuaded.
The first time somebody told me he was down I had to pause and wonder what he meant. Did he mean he was sad? Did he mean he didn't want to do the thing?