Just recently I was in a conversation with a number of UK mainlanders and we had a debate over what “tories” meant, apparently disproportionately ordinarily it refers to a political party and it’s not usual to use it as short for “territories” as I’ve used it (according to how the debate ended, it was half and half between them). And once again I’m reminded of how people feel to look back at their usage of a word/phrase over the years and cringe.
More tragically, me and a friend were embarrassed once upon realizing everyone was confusing “encephalitis” with “hydrocephalus” when talking to someone about their kid with hydrocephalus. Awkward because encephalitis is caused by HIV.
“Effect” is a noun, while “affect” is a verb. You can cause effects, by affecting something. “Affecting” is the act of causing effects, while “effects” are the actual causes of an affliction.
As an example, let’s say you get drunk. There are two different ways to phrase the same scenario: you are feeling the effects of the drinking, or you are being affected by the drinks. The end result is the same, but you need separate words for them.
In the former, you are feeling the effects. Feeling is the verb, effects is a noun. The same way you would feel the clothes against your skin, or the ground beneath your feet. But with the latter phrasing, the drink is acting upon you, so you need a verb; You are being affected by it. The same way you would be affected by someone else in the bar pushing you. Falling over is the effect, because you were affected by the push.
Effect and affect are both verbs. They are also both nouns.
effect n. meaning as you described: “The effect of the potion was that I grew three sizes.”
affect v. meaning as you described: “The potion affected everyone the same way.”
effect v. meaning “to successfully cause”: “The potion I’m mixing will effect a revolution among the goblins.”
affect n. meaning face or appearance: “Realizing she was about to drink the life-changing potion, the goblin’s entire affect shifted to delight.”
You know that the other two words also exist though, right? Like, you can effect change in an organization, and there can be something strange in the affect of a psychopath. So there’s a verb “to effect” and a noun “affect” (although here the pronunciation is different–the accent is on the first syllable). It’s true that the most common usages follow the rules you’re laying out, but it genuinely is an oversimplification.