It really depends on who it is, and what there personality is.
For some people simply just saying, "yeah" to someone after everything they say can get them to cuss and scream.
In a discord call, there a good couple.
When ever someone asks you for something,
respond with 'You won't need it where your going". I would recommend muttering that though.
End every sentence with "According to the prophecy" or something idk how to spell
Ask them weird question, and mutter something about "Phycological Profiles" or something idk how to spell
Scream at them and get angry over nothing.
For others who know how to control there cool, it can be a little harder.
For Minecraft, spend money/currency on useless items and visibly express it. Try to bait him/her into an argument about the subject. This will eventually get them annoyed at least, and if they didn't get annoyed via the first method, they probably might not now.
For forums here;
1. simply spamming images
2. ONLY TYPE IN CAPS
3. Begin all your sentences with "Oh la la!"
(tbh I don't know why this would annoy someone"
And you really can't be to annoying while being on forums compared to IRL.
Some ways to be annoying IRL;
1. Honk and wave to strangers.
2. Drum on every surface.
I mean EVERY.
3. Finish the 99 bottles of milk song.
4. Pay for dinner with pennies.
5. Repeat everything someone says as a question.
6. Name your dog 'dog'
7. Lick the filling out of all the Oreos, and place the cookie parts back in the tray.
8. Make beeping noises when a person backs up.
9. Mow your lawn with scissors.
Yeah, can't be bothered to list more.
Uh if you want more,
click here