I don't like office affairs because some times innocent colleagues get caught up in the maelstrom of romance/lust.
This happened in an office I worked in... every time I spoke to the guy, his girlfriend, my supervisor got jealous. both were married and then we are left in the situation of complicity at office parties when their spouses were there.
I did not like it!
I want to do my job in a pleasant environment - take the money and enjoy my free time.