-When you purposely picked all your classes to be on Tuesdays-Thursdays only, Mondays- Wednesdays are off to do MRs since those are considered "cheap" days to do MRs. (me

)
-When the first thing you go to is the "MR forum".
-When all your bookmarks are travel related sites (kayak, ITA matrix, mileage calc).
-When you plan to give an "Informative Speech" about MRs without any notes for Public Speaking class.
-When you read threads like this to see if anyone forgot to mentioned something else.

^