Just quickie, a list of ten, not necessarily the best or anything, so please feel free to add any of your own in the comments.
You know you play Ingress when:
- You feign being lost in front of portals, to not arouse suspicions while you hack, burst, deploy or upgrade.
- You do the scanner moonwalk, which is what happens when you want to deploy resonators as far away from the portal, so you walk until it is just beyond the edge of your scanner's field, and back-up to get it right on the end
- You have the volume just a little above inaudible, so as to see if other operatives reveal themselves from the masses around you, when they react knowingly and look around to try and find the source
- You carry around your laptop as a back-up portable charger until you can get a real one
- You now realize just how many post offices and libraries there are in your area
- You know the city speed limit allows you to hack about a portal each block, two if they're close to the road, spread out enough, and you're quick
- You actually slow down to stop when you see a yellow light, because it let's you do more damage to that portal right on the corner
- You actually want the red light to last longer, so you can finish deploying, upgrading, or linking
- You will drive in the left lane just to be able to hack that portal just on the other side of the street
- You recognize the screen's glow at night when another car pulls up near you
Disclaimer: for any of the car references, it is assumed that there are two operatives playing, one to drive, and one to use the scanner, as it is dangerous and illegal in some places to use a mobile device in your vehicle without a hands-free accessory or setting.
Anyway, that's all. Have any others you'd like to add?
Leave 'em in the comments :-)