I was surprised to find out how many men feel that tears are used as a form of manipulation. While there may be some women that do this, I think the vast majority of them do not. Like some of the above posts have said, I often wish that when I am trying to discuss something important that is also very difficult, I would do anything to keep from crying. Tears never come unless it's out of extreme frustration after superhuman efforts to make something work and exhausting every possible option to no avail (this could happen in a work setting, but not in front of anyone if I can help it) or when I am talking to someone and the emotion is extremely deep and tear slip out against my will. There may be a sum total of three people in my life that I would ever consider crying in front of and those occasions would be very rare.
If anything, I wish I were much less transparent in those situations. I understand that tears invoke inner bad guy accusations for the other person and also put me at the disadvantage of looking irrational and overly emotional. It certainly isn't to my advantage.