Being white and male and middle class generally means that, wherever I am in the world, I'll get the benefit of the doubt in most public encounters. This doesn't apply in my home, obviously, or on Twitter, but in most real-life encounters people will be inclined to assume that I'm not an illegal immigrant or a bag-snatcher or a suicide bomber or falsely crying rape or the guy who left the orange peel on the floor of the lift.That's the way white, male, middle-class privilege works, and it usually works so seamlessly and invisibly that I'm not even aware of it, and unlikely to spend much time thinking about what it would be like to not be me. It takes an unusual incident to give some brief flash of insight. For me it was the pharmacist at my local dispensary.Yesterday my wife had reconstructive surgery on her hand, involving skin grafts and deep anaesthetic and the prospect of much pain when the anaesthetic wore off in two hours' time. I'm not a natural nurturer, so when people are unwell I'm always grateful to have a practical task. I left her propped up in front of the Kardashians - a powerful central nervous system anaesthetic - and trotted off to fill a script for oxycodone, the schedule 6 drug much prized by moneyed detrimentals and celebrities who prefer their opiate addictions to come with prescriptions and blister packs.It was a cool day but I'd been dawdling about the house looking for my keys and watching a bit of the Kardashians to try to see how Bruce Jenner's looking nowadays, so I walked briskly because I didn't want the anaesthetic to wear off while I was still out there and I was lightly sweating when I arrived at the pharmacy to find a long queue of malingerers and hypochondriacs. I tutted and fretted and hopped from foot to foot, furling and unfurling my prescription like a tiny cheroot, muttering "Come on, come on" at the old duck describing her ear-wax problem to the man behind the counter. Normally I'm good in queues, but I was worried about my wife, so this time I wasn't.Finally my turn came and I stepped up and slapped down my prescription. The pharmacist looked at it, then he looked at me. We instantly disliked each other. Pharmacists are a miserable bunch at the best of times, but this one seemed particularly disgruntled with his lot. He was hunched and furrowed as a walnut and had eyes like shucked oysters. I could see that I wasn't making a good impression on him either. I was wearing paint-stained jeans and a James Bond T-shirt and an old cap with "Cuba" on the front. It's not what I'd wear to a business meeting, but this was just the pharmacy, and it's not like he'd made much effort either. He was wearing a grubby white coat, presumably in the hope it would make him look like a doctor.He scowled at the prescription, then glared at me as though I was personally responsible for all the disappointment he'd caused his father."It's not valid," he said. "He's written it in numbers, not words. I can't fill this out.""You have to," I said. "My wife will be in terrible pain in about 30 minutes.""Then your doctor should have done his job," he said.There was no point calling the doctor because I knew he was in surgery, and it was after five so his office was closed. I tried to tamp down the rage and give him the middle-class white-man smile, the one that says: "I know there are rules, but surely they're not for us. They're for the other people, the criminals and troublemakers. Surely we can work something out.""This isn't a real prescription," he said. And suddenly I realised that he thought I was a white-collar dope fiend with a fake script, trying to score some oxy before the shakes started. I matched the profile, and the more I tried to act as though I didn't, the more I did: now I was sweaty, agitated and trying not to appear so. He had an idea about me, and everything I did - everything I am - confirmed that idea.Eventually I used some impolite words and snatched back the prescription and stormed out and ran home. My wife was pale-faced on the sofa. She had maybe 20 minutes before the pain started."Did you get it?" she said anxiously.But I didn't answer. I knew what I had to do. I smoothed out the prescription and shaved and put on my new suit and drove to another pharmacy. Because in this world we've made that's what white, middle-class men get to do...