I wouldn't say I hate them, but I'm definitely not a fan in general. I have been playing some 2048, played Flappy Bird and Angry Birds, usually keep a chess game around.
The thing I don't like is that they're not like the games I grew up with. It's pretty much as simple as that. At a young age I got introduced to games, and as I got older became fond of them. A game to me, will always be a physical product, made for use with a device intended only or very primarily for playing games. I liked that. As things change, turns out I'm no longer 'with it'. I'm old fashioned, I like the ideal of a game that I remember. I'm not big on the idea of general purpose machines that also play games. It suggests that games aren't important. And besides that, the console/handheld and the idea of its library is part of the fun for me.
I don't like mobile games. I also don't like online requirements, downloadable games, patches, DLC, free to play models (that involve ads or possible payments). It's not really that these things are bad. It's more that I'm a grumpy (metaphorically) old man who's set in my ways. And that's fine, I kinda look forward to seeing video games as I know and enjoy them decline... it will give me plenty of time to catch up and collect with older generations of games. Even with that attitude though, it's hard to see bits and pieces of it happen. When classic IPs or developers go with mobile, of course that's initially disappointing. Because for me, that's wasted potential. The eventual Shenmue 3 for iPhone announcement will make me wince hard.
It is kind of annoying how often traditional game players aggresively push the opinion that mobile games are wrong and you're a bad person if you like that. I fall into doing it sometimes too, as a knee jerk reaction to things. The goal though, should probably be to respect other peoples opinions, and avoid discussion topics involving things we hate.
There's also the fact that touch only controls aren't the best for plenty of games... trying to play Mega Man or Sonic on some friend's phone left a bad taste in my mouth. That practical concern isn't really applicable for well-designed mobile games though.