We've all heard of people who have a way of putting themselves first. They always look out for #1. The interests of others are only considered if it happens to be convenient or if there is some benefit for you-know-who.
I may be far too optimistic, but my guess is that those selfish souls are far out-numbered by people who are so selfless and generous, they have to be reminded to consider themselves. These people are self-sacrificing in the best and, yes, the worst aspects. Their dedication and ideals may become self-inflicted wounds.
There has to be a middle ground between being a selfish jerk and being a selfless martyr. The trick is deciding just where that ground is located. My suggestion is that this become a topic for discussion at company retreats and meetings. Many a martyr may believe that such conduct is the only ethical course of action. If that belief is left unchecked, we can lose a lot of good people.