During the sixties, many times someone would comment on something by saying 'Heavy.' Of course, it had nothing to do with the 'weight' of the statement, but referred to the seriousness or importance of what was said. The other word that was (over)used was 'Groovy.' But we won't go THERE. ;)
I have several quotes that I consider 'heavy'--and they give a lot of bang for the buck in terms of being able to sit and ponder what really is being said. I now give you, 'Heavy':
--"It is better to remain silent and be thought a fool than to speak up and remove all doubt.'
--"Life is what happens when you're busy making other plans"--John Lennon