The title may not make sense to you if you are new to reselling products, but the idea is that most of the people who get loaded with inventory that is not selling tend to buy products they personally like and think others will too. One of the early lessons I learned in resale was that it was the rare, the unique, and the thing I would never have any interest in that would tend to sell well. There are some products that I like that sell well, but if I amassed all my inventory based only on things I like then I would be a disastrous failure.
For the newbie, my advice is to not get caught up in only buying things you like. Do not misunderstand this as telling you to avoid buying items you are an expert in. You should buy those items you have an expertise in, but just because you like an item does not mean you have enough practical expertise in that category to know what will sell best. As a newbie you should be scanning everything you can get your hands on. Only with time will you develop the skill-set and practical knowledge to be more picky in which items you choose to consider for purchase and which you ignore. Ignoring items simply because they do not interest you is a sure fire way to miss a lot of potential profit.
Scanning items in retail arbitrage is extremely easy, but to be able to find profitable items may not be so easy. Do not limit the items you might research by scanning until you already know from your own research that those items are not worth buying. I remember the first time I saw a cross-stitch kit at a clearance section of a retail store. It is not something I would ever be personally interested in, but I scanned one, then another, then another, and left within minutes with about $500 worth of potential profit in a small amount of cross-stitch kits (all of which sold within a few months). Had I been looking for only things that interested me I would have literally been passing up easy money. Also, I now learned that there was real profit potential in cross-stitch related items, and so I can keep an eye out for them and find more profit while others ignore them.
Make sure you are not the person passing things you have never researched before. Research, research, research, and keep at it. You will be a success in retail arbitrage if you will never give up!