AMPS... if you've ever owned a GREAT amp, like a Marshall 18 watt, a VOX AC15 or a Marshall JTM45, and if you have a place where you can crank them up loud, then you know what I'm talking about. Smack a power chord and you (not only) hear the fundamental notes, but you get (count 'em) 4, 5, even 6 additional overtones ringing into a feedback... notes that you can whistle if your ear is good enough! Think Zep's *Ocean* or *Custard Pie* or classic tones, including James Gang, the Beatles, AC/DC, Free., and so on.
Back off the guitar's volume and there are a dozen great other sounds at your fingertips... Clean, spanky sounds, with all the highs and lows still intact. And a Tele still sounds like a Tele, a Les Paul like a Les Paul.