Because Breaking Bad doesn't have that 'Look at me I'm watching a show made for 8 year old girls. Aren't I edgy?' feel to it. I'm not saying that's why everyone likes it, but I'd wager it's a good portion. That's part of it. I like it because it reminds me of when cartoons actually were worth watching. Instead of all of the [cabbage] we see on tv today. You're viewing everything through rose-tinted glasses, as nearly everyone does with old cartoons. You enjoyed them as a kid, grew up, and can't enjoy the current. It's not that the old cartoons were necessarily better, you just remember them as being awesome.