If your garage sink has sprouted strange blue plumbing...
If you spend hours in the hot sun with a magnifying glass and a stop watch
staring at streams of water..
If you can quote the National fire protection standards for cryogenic fluids to the code enforcement officer, without notes.
If you know exactly what chemicals are used to denature ethanol, and can quote the stock numbers for the different types from the local chemical supplier.
If you collect strange copper sculptures.
If you know the density of several kinds of alcohol in both English and metric units.
If you have a sleepless night worring about how to rotate an Inertia Tensor
(And your friends solve the problem by return E-mail)
If you have a weekly conference call to a federal agency to explain how you problem is going...
If one of your buddies stops by to visit on the weekend and the first question he asks "are there any stainless chips in the chips on the floor" He's barefoot and his feet are just fine with aluminum chips, but they are not yet tough enough for stainless.
If you are proud of your AN fittings collection.
If you know the hours of and directions to the McMaster Carr will call window.
If you this looks like you, you have arocket problem, seek help.