Amazon

Amazon isn't the platform you fall in love with — it's the one you never really leave. Over 200 million people pay for Prime, and the site carries more than 350 million products, which means the question is rarely whether Amazon has what you want but whether you can be bothered to look elsewhere. Next-day delivery, painless returns, and a review system deep enough to actually be useful make it the default first search for almost any purchase. The catch: for anything niche, handmade, or genuinely cheap, better options are further down this list.