Do you have zero interest in an expensive mountain bike the company you are an affiliate of sells? Well, you probably don’t want to feature it on your blog, as it is extremely difficult to persuade readers (or anyone for that matter) that they should buy something you wouldn’t be caught spending a single penny on. When you are passionate about a product or–at the very least–interested in learning more about it, this will come through to your readers, engage them and better coax them to buy
For example, if I talk about how cool a product is, and then you find out that I’m an affiliate for them, wouldn’t you as a conscientious observer become skeptical as to whether my information is biased, if perhaps I’m only saying how cool something is because I can get paid for it? Wouldn’t that make you question my integrity with other things I say as well?