Here is a funny quote from Vint Cerf, who said at the linux.conf.au 2011 keynote:
"So, IPv6. You all know that we are almost out of IPv4 address space.
I am a little embarrassed about that because I was the guy who decided that 32-bit was enough for the Internet experiment. My only defense is that that choice was made in 1977, and I thought it was an experiment.
The probem is the experiment didn't end, so here we are."
I love the understatement Reference: LCA 2011 Keynote video.