My work colleagues are not my friends. I already spend more time with the people at work than I do with my friends and family... so why would I add my half hour lunch break to that already unreasonable amount of time spent with people who I don't choose to spend my time with?
Don't get me wrong, I get on with most of the people at work, but that's as far as it goes. Bosses bang on about how work is a family blah blah blah, but only when it suits them to get something done (for the most part).
I also work in an office with no windows or natural light, so time spent in the car park nets me at least a little bit of sunshine. Add to that I'm pretty comfortable with my own company; some of the admin girls say things like 'oh, jumpy always spends his free time alone, I wouldn't like to spend that time on my own all the time'. pfft, go back to watching towie love.
And I get to listen to a radio station that my colleagues won't moan about (R4 if you must know). If there's too much talking they start getting twitchy. We settled on 6music that works fairly well.
I do sometimes have a snooze out there too. Had a complaint before about that: 'not very professional of jumpy sleeping in his car at lunchtime, what if a client were to see?' meh, if you saw the dilapidated state of the car park and the signage you'd be more aware of a lack of professionalism, than seeing me stretched out on the back seat.