I deal with shoplifters on an all to regular basis - I don't think its too hard to figure out my job. I've locked up just about every range of society from the drug users after their next fix right through to 'respectable professionals' after a thrill. I recently arrested the son of a very famous sportsman who has more money than I'm likely to ever have. I've seen the most bizarre items stolen for no fathomable reason. Quite simply, there is no set picture of a shoplifter and their target items.
The OP has had a bad experience - thats beyond doubt - but the manager has made amends. I don't expect the OP will ever set foot in PC World again - thats fair enough, and a personal choice.
I hardly think that most shopkeepers treat every customer as a potential thief, but they have to make a stance when they think they are being targeted. Unfortunately, as in every walk of life, sometimes they're wrong. I'm not trying to defend PC World in this instance, just point out that sometimes you need to move on. If you can't do that I'll book you a place at your local hospital for your next bout of stress related illness.
Anyway, some people are happiest complaining, I've stated my opinion, and its time I withdrew from the thread
Happy shooting