The following are a few of the things that really annoy me or make me laugh in creepypastas.
The first letter of each paragraph spelling something out like,"Don't look behind you" or "You're Next" isn't scary, it is just hilarious to see how bad this is at shock value.
Ending the story in You're Next or Look Behind You. Just funny.
Starting the story in I'm not gonna have enough time to write this or This might be my last diary entry et cetera. This is hella annoying and kills suspense.
Mentioning BEN, Jeff, Sonic, Zango, Cleverbot, and also making a crappy spinoff.
Mentioning serious topics such as rape or abuse without maturity. These things are very serious and will most likely offend people, such as me. Not to mention how many people will go through rape or abuse. Also, treating people who do this like badasses.