If you make a habit of this then you very likely have the intelligence of a twig.
Why? First of all, there is nothing to gain from it. When parking in a standard lot there are usually two options, not counting parallel parking. So your job is to pull in and pull out. Backing in has no advantage and you screw everyone else up. Your backwards choice means you have to make that angled move to the opposing row and right there people are wondering what's next? You can't make use of your signal lights as you can with the front end first option so only you know what your next move is. When you make it you're outed as an idiot.
Most people I assume want to get in and out of where ever they're parking a.s.a.p. and you back in first dullards are messing it up for the majority.
Back to the "in and out" options........somewhat sexual connotations perhaps. Maybe the back in first boys have no conscious control of this act.