I'm always suspicious of people who include certain phrases or descriptors. Things like:
I think deep thoughts. Uh. I don't even know what that means, but I suspect it's something along the lines of, "I have a high opinion of my opinions, and you should, too." Deep thoughts? Really? If it's not obvious from conversation, it's probably not true.
I know you said you like X, and I'm Y, but.... Now, I'll grant you, sometimes -- very occasionally -- someone will have something good following the "but..." in this kind of statement. Maybe he'll have a different take on the whole X/Y division or he'll be outside of it in some interesting way, but... almost always, that line is a lead-in for a long paragraph that I can sum up thusly: "I disregard your opinions, because they don't match with mine. Isn't that hot? Please do me."
My sign is ... What's yours? Is this the 70s? Do you really think this matters? Either you do, and, hi, let's not get into that, or you don't, and you're just using an outdated, slimy pick-up line! I'm amazed how frequently I get this one.
I like girls who... I actually use "girl" to refer to myself and my (wait for it) girlfriends with some regularity, just as I frequently use "boy" to describe my male friends. But very few of the guys who put this in their email seem to use it with any self-consciousness, and it just makes me fret a bit. I know they really mean women, and they'd no doubt say I'm making a big deal out of nothing if I raised a stink about this, but it nevertheless rubs me the wrong way if there's no indication of understanding the complexity of it all.