The song Machine Gun is a perfect example of tapping into something dark.
If you can find it, Jimi Hendrix’s “Live at Berkeley” is all dynamite. He taps into something on another level that’s the opposite of dark. Another favorite of mine is Jimi Hendrix when he played Royal Albert Hall in 1969. That whole show was on another level.
Writing is the same way. You can either tap into something dark or something ambitious. A good writer should be able to tap into both.
Tapping into one source will only limit your potential.