I gigged a room once and every time I played a G note the room - not an 80lb combo, the friggin' room, rattled. "Can you not play that note?" asks the sound man! My response was along the lines of "Ach away and F**K right off! The only sympathetic thing you'll hear in here tonight mate is that vibration now get it fixed and do your job."
I miss the good old days...*sigh*