Taurus and Libra
At the beginning, you'll notice it's all right if you are a little overbold and more insistent with a Libra, because (s)he's so diplomat and charming. But you'll find an obstacle precisely when you are very confident about your chances: even if Libra exteriorizes the way we know (s)he does, deep in his/her heart (s)he is very determined, with very clear opinions about anything and anybody, and not at all passive.
Your inertia and inflexibility? That's exactly what your Libra will use to conquer you (or against you), but (s)he'll do it step by step. So, as charmed as you'll be by a Libra, you'll feel like you don't have anything to hold on to this Air sign. Well, I know how much you like flirting and the beginning of a relationship, so that won't be a problem.
Moreover, Libra will be very scared at the sight of an angry Taurus (who wouldn't be? They put on shows with angry bulls in Spain...) and (s)he'll feel like running away. (S)He'll be back though, because Libra likes the stability of the Earth (Taurus) and his/her irresistible charm will make your annoyance fade away.
Libra likes going out very much (much more than you do), because (s)he needs to walk around, to be accompanied by other people. Taurus is more of a family man/woman... and it won't be very clear to him/her how it is possible for anyone to have so many friends at the same time!