There was a discussion on Feministing that moved from talking about why men can't cry to a discussion with a single poster about how he, personally, cannot feel emotion and thinks that the human race would be better off without it because they would not feel suffering.
Here's the thing. I believe that there is a powerful value to emotional suffering. We may not realize it at the time, but emotional suffering can give us strength and make moments when we do not feel it all the more powerful. If you never suffer, you never really fully live.
What's more, there is a lot more to emotion than pain. Most emotions are not painful. The poster I was discussing it with says he does not need love, though it's not really a question of needing. When you feel love, anything is more bearable. Starving? That's okay. Poor? You can bear it. Ostracized from society? Sucks, but you can pull through. The emotion doesn't just tie you to a person, it makes all the negative aspects of your life no longer seem as bad while still making you want to eliminate those aspects-- not for your own sake, but for the other person's. And yeah, love can end in pain. But unless it was an unusual amount of pain-- like you break up and they burn down your house and kill your brother, which is why I don't recommend dating people who are batshit insane-- in the end, the remembered emotion and the drive to find it again, to make the parts of your life that you can't control better, makes the pain worth it.
And passion, which is literally the driving force behind science, medicine, and art. Why study ecology, for example, especially if you're not doing it for money like most early ecologists? Because you have a passion for nature. You are passionate about what you are learning. Why travel the world and learn about other cultures? Because you care about the people, because you feel awe at the natural and man-made wonders. Most early scientists made no money except what they got from patrons, but they loved what they did, they wanted the prestige of discovery (pride) and they were passionate about their work. Otherwise everyone in Ancient Greece would have been landowners or farming serfs, and there would have been no interest in the arts or science, thus eliminating our basis for modern scientific method. Most of our inventions in daily life are born of necessity, not passion, but they could not have been made without practical application of theoretical ideas that gave no material benefit to the scientist who came up with them-- only the thrill of discovery. And even if you say "They do it because they will get more support from benefactors" keep in mind, what gain are benefactors getting, besides learning more about that which they are passionate about?
To an outside observer, suffering seems to be the most common emotion. And I guess if you're a starving orphan with AIDS in Africa maybe it is. But suffering's not the most common emotion, just the most visible. I feel very powerful love every single day for my family and my boyfriend. That doesn't mean I'm always singing it's praises or doodling hearts in my notebook. I feel passion every time I write or read something I'm interested in that makes me want to read on, but that doesn't mean I'm telling everyone about it. Suffering is lessened when there is emotional support from others, so we complain about it so that others will sympathize. So I guess to one who feels no emotions, it would appear to be the most prevalent simply by virtue of the fact that that's the one we seek support for. That's the one we talk about.
A person who feels no emotions is only living in the biological sense. If you can't see natural beauty, if you can't wonder at the cosmos or feel passion about your work or get angry with a friend about the idiocy of some politician; if you can't lessen the pain you can't fix through love or experience joy when something wonderful happens to you, you're not really living your life. You're just... living.