There's no reason to hate Bose the brand, but perhaps you can hate what it's done to the general publics understanding of audio. You can certainly find plenty of info on what makes the Bose products "not great" around here and on other forums, as well as at various websites such as this one: http://www.intellexual.net/bose.html
I don't personally care one way or another about Bose. I own a Wave CD/Radio but I would have never bought it, I inherited it. It's one of the best sounding tabletop CD/Radio alarm clocks I've heard, but I haven't listened to the other items on the market which from what I've read sound better (such as the less expensive Cambridge unit and various others). In an absolute sense, it's a ripoff at $500 IMO.
As far as the rest of their speakers, or their cubes, they simply don't sound that good to me. Even in absolute measurements they tend to fall flat on their faces. Particularly the cube systems (as you'll see in the link I posted). So if you're looking for sound quality, while no doubt some people think they sound good, I'd wager they would change their mind if they listened to other products.
Some buy Bose because of the size or how they look (I think they're ugly and cheap looking but YMMV). They generally rate well with WAF for those concerned with such things.
What's bad? Well like I said audio quality is below that of much less expensive products, and they can cost as much as some serious audio gear. Does that lead me to hate them? No, they're quite successful at what they do. What I do hate is people who don't know anything about audio walking around like they know something because they have heard or owned Bose. It's equivalent to someone walking in to a room of photographers and telling them how their big SLRs are a waste when their little point and shoot does such a good job. It's on such a different level that many people simply can't comprehend or understand it until they've had some experience with it. That's what I hate about Bose, but again it's not directed at the products or the company, but the people that worship them I suppose. Fancy marketing and gadgets don't fix a flawed or incapable speaker system. Fancy sensor cleaning modes and gadgets don't fix a camera with a lousy lens system or flawed sensor either.
Would I buy Bose for myself or others? No I would not, and I will always gladly help and explain to someone who asks for information on them and wants to really know what is out there. I've helped several people I know shy away from Bose and buy things that cost them considerably less and they found that those products sounded much better. You can't deny the cheap materials and deficiencies in sound reproduction that Bose exhibits, however those may not concern some people, and others simply don't know.