...you refer to a new music release as an 'album' and people look at you funny.
...one of your daughters high school friends is dancing in a nookie bar to help pay her tuition.
...you notice some of your favorite music is only played on 'classic rock' stations.
...you look under the hood of a car and think, "Jeez, what is al this crap?"
...you first hear the word 'blog' and think it's some D&D critter.
...you realize many of the Saturday morning cartoons were made for adults, not kids.
...somebody tells you you dress 'retro'.
...somebody freaks out because you carry a pocketknife.
...they'd REALLY freak out if they knew about the .45.
and so on...