[quote=Mach2]
Your original characters have conversations in your head. 

You've stayed up to an ungodly hour waiting for someone to post.
[/quote]

[quote=Gonzo]
You know you have a RP problem when...You reference a joke made in an RP to your RL friends who don't RP, and they have no idea what you're talking about.

You ditch homework to RP instead.
[/quote]

[quote=Jannah]
You know you have an RP Problem when you've lost sleep over thinking about how your characters were going to react in certain situations in the RP.
[/quote]

[quote=Mousia]
You know you have an RP problem when you spend at least an hour explaining the concept of a certain RP to a friend who has no idea what RPing even is.
[/quote]

[quote=Wolfling]
When your roleplay is dropped and you feel like you have to explain to your character why you can't write him anymore.
[/quote]

Ditto to all of these. Yes, all of them.

Additionally,

When you load IC threads on your laptop browser before you leave home in the morning, so that when you get to school, where you know you won't have access to wi-fi or any other means of access to the site, you will still have the threads to look at, so that you can write responses in a word document and post them when you get home.