I dunno about you, but I've sorta become dependent on plastics. I suppose if I had to, I could just convert my car to run off of vegetable oil, but I need plastics in all parts of my life. Like this keyboard I'm typing on.
The story behind Alien (the book, didn't see the entire movie) is good. The crew is basically an oil barge taking oil pumped from other places back to earth not for fuel, but to make plastics.