Not sure if this belongs here, but how do you test a tube amp in a store because, I've heard that to hear a tube amps best you have to crank it. How would I go about doing this in a store without looking like the world's biggest douche?
If you're think you're going to walk out with a new amp theres no reason why you CAN'T crank it. Hell, if you're self conscious ask the clerk to give you a demonstration of the "natural breakup" or something.
Let me tell you about heartache and the loss of god
Wandering, wandering in hopeless night
Out here in the perimeter there are no stars

Out here we is stoned
everyone does it. when you go to guitar center at least 5 people are always playing something really loud and sometimes they suck, like this one kid i saw the other day playing nothing but palm mutes and power chord but he was playing really loud. go with the flow and do what other people do.
Most guitar stores have a sound proofed room for that sort of thing. If you let a salesperson know you're seriously considering buying an amp, they'll likely let you try an amp in said room.