Even as a consumer (with an augmented short-oil position), I find it hard to be insouciant about oil prices as low as this. Something's gonna give. Politically, economically, socially, all three ... Saudi, Russia, Nigeria, all three ...
Then there's Shell and its BG gambit. Trying to emulate John Browne's BP (1998) by cleverly buying assets at the bottom? A hopelessly mis-timed play.
(Incidentally, in moving on gas-heavy BG they were doubling-up on their already humungous mistake of pouring $$$ into Qatar LNG, which Shell insiders swear they never would have done if they'd seen this coming ...)
Then, there are the legions of very nasty people who've made their 'livings' from quietly skimming off oil profits (which ain't too difficult @ $120, but altogether harder just now). A bit like when drug dealers can't deal drugs any more, they will be looking for the next source of ill-gotten $$$: and what, do we think, might that be? We won't enjoy it, whatever it is - because it's our money either way.
'Interesting times' doesn't get close.