I've been adding to Tom Sevart's hilarious list, which is here.
So far I have:
You not only know what WUN stood for, but why it became UDXF.
You actually look for stations sending 9th-pulse LORAN-C.
You can identify particular Cuban numbers transmitters by their respective technical flaws.
You miss those voice loops that began "This is a test transmission for circuit adjustment purposes..."
You know that General Pacheco was not a character in an old western movie.
You've tried to track chirpsounders with the sweep function on the NRD-545.
You added the solar flux extension to Firefox within 24 hours of learning it existed.
You have an old audio cassette around somewhere from the last solar maximum.
You can tell the difference between military RF feedback and Globe Wireless spurs.
You know who to e-mail to get either of these fixed.
You routinely attract the interest of DX-Tuner site operators.
You remember when the WWV Geoalerts were in Morse code.
Your Google Earth placemarks are mostly antenna farms.
Your own antennas are visible on Google Earth.
You walk around gambling casinos looking for the slot machine that sounds most like XSL.