…you press B or C to try to select more than one icon on the desktop(true story, gave me the idea for this thread.)
…you study someone’s head until they look at you funny to observe their proportions and topology.
…you dream all night about recalculating normals.
…you talk about Blender until your friends rip your clothes off.
…you spend more time in Blender than you do sleeping.
…you blame being late on taking too long for your ride to render.
Anything else from anyone?
I have the problem, that i try to select all via pressing “a”. 
I talk with my friends about polygons and textures, while looking films or look at pictures.
Merry Christmas
When you write descriptions of Ambient Occlusion, Bokeh, and Chromatic Aberration on the whiteboard at school, because you are surprised that nobody else knows what you’re talking about. (True Story)
When you think that you have been using too much blender.
Merry Christmas back! And happy winter solstice…
when you imagine how is the wireframe of everything around you
when you’re at the beach looking to a fantastic sunset and think “this looks fake, Andrew Price could do it better”
…when you look at a wet field and try to find the specular settings of the grass.
…when you wonder how on Earth the sun’s lens flare was composited.
…when you are on your computer desktop and press Ctrl+Alt+U to try and bring up the properties.
When you assign an XYZ location coordinate to everyone around you on the bus.
When you see a CG image, and try to pan/zoom/rotate it. Happens several times a week to me. 
…when you try to look down upon a picture to get a different perspective.
When you model an entire house and wake up to find it’s been just a dream.
When Ton catches you hiding in his garden. And once again I’m sorry about that!
…when you go through plastic surgery to look like Ton.
…When you try to use grab, scale, pan, and zoom shortcuts from Blender in Adobe Illustrator. (happens all the time for me and every time I’m disappointed I can’t use those shortcuts)
When you press X to delete stuff in other programs (happens to me every couple days)
When you see real world objects in wireframe mode
When you try to guess the vertex count of real objects
When you dream about Ton
When a new blender feature is announced, you feel weird in the pants
When you have nightmares about triangles
When you can actually relate to geometry class a bit better by using an example through your adventures in 3D…
Yes… but I hate my geometry teacher.
…when instead of using Blender to relate to geometry class you use it to prove points in nerdy geometric arguments with equally nerdy friends.
BWAHAHAHa!!!
… When you watch paranormal activity 3 and spend the whole time talking about how they did all the effects and not paying attention to the films plot. ( Happens to me in almost every movie I watch.)
Pressing X to delete things. (Unlike ldh it happens to me more than just every couple days.)
Imagining the world as a wireframe.