A few years ago, we had good chuckle in our electronics lab after someone pointed out how we continously swapped back and forth between metric and imperial units, depending upon what we were talking about.
For example, if someone was complaining that the lab was uncomfortably hot, he'd say something like "Man, it must be 80 in here". A couple minutes later, if someone asked him what the temp was when he took some measurements on something, he'd say "Oh, somewhere around 27."
The funny part is that until somebody pointed it out, most of us just unconsciously and automatically used metric units for lab work and imperial units for everyday conversations without even realizing we were jumping back and forth.