Okay, Mama Kat. I've had to slightly modify your writing prompt. Because, really? Narrow my pet peeves down to one, single, biggest pet peeve? Yeah. That's a task of, like, epic proportion. Supercomputers at NASA or Microsoft or somewhere SUPER smart like that would be necessary to start to break down the complicatedness going on inside my brain to even begin to come close to narrowing down my pet peeves to just one biggest pet peeve. If you ask those in the know, they'd probably tell you that I hate everything, but that's SO not true! I'm just a ridiculously picky snob. ;)
However, dear Mama, it was so simple to pick my number one writing pet peeve that I just added one little word to your otherwise brilliant prompt. So, let me break it down for you.
Fellow human beings of the world-- these words are NOT interchangeable.
An impact is a collision of some kind. A force of two things coming together: BOOM! Impact.
An affect is the result of something, but not something that hits you .
For example: The overwhelming sadness of the move to Oregon had a significant impact on the boy's developing social skills.
NO! NO! NO! NO! Did the poor boy get physically hit by his move to Oregon and an invisible force went ninja on his future social skills? I'm going to say that's doubtful.
The overwhelming sadness of the move to Oregon had a significant affect on the boy's developing social skills. Ahhhh. Now, doesn't that feel better? It sounds better and, more importantly, you're using the RIGHT WORD!
Now let's get to punishment...I've had to really think about this...You get to be a crash test dummy. Be part of crashing a car right into a wall so you can tell me how the impact affected you. :)