DancingWriter, I understand your opinion on the matter of charity, but I feel you are still misunderstanding the actual question that I asked.
I'll try to word it differently. Take the 'falling on a grenade' example that was just posted by meikle above. It demonstrates an act that most of us would not consider one of "self-interest," since most of us in this thread are using the everyday, working definition of what self-interest means. Most of us define "self-interest" as pursuing something of tangible personal benefit - be it for money, respect from the community, status, ego, etc.
On the contrary, it appears that you define "self-interest" as being much broader. For example, if someone donates money to a charity purely out of the goodness of their heart, you would still consider this an act of "self-interest" since you claim this is motivated by their desire to not feel guilty for not donating, and thus the "self-interest" would be their desire for psychological well-being. Am I correct in this understanding?
I acknowledge that you, and many others, may fall into this latter category, in which case, I can understand why you are choosing to interpret self-interest in the manner you are. But my question is, on what basis are you projecting this line of reasoning on all human beings? Clearly as evidenced by the responses in this thread, many people are not motivated by the guilt of 'not' being charitable.