s4ndm4n2006 summarizes what I would say very well.

The only thing I might say different is where "unconditional" comes into play. The older comments have good points on that. I'm torn where I want to say it's not exclusive to parent/child relationships. Other family relationships would fall under that too I think. In those cases though it's because you "have to" - you're stuck in the relationship until the end of your life so unconditional in this case is forced. Of course, you can hate your family, but you're also more inclined to try to forgive them because of what that relationship means. Hope I'm making sense. >.< Unconditional doesn't make it better I don't think.

My problem with conditional love is the conditions. Some people have too many or are unreasonable about them. I'm probably one of those people thanks to my MI making it hard for me to trust and feel secure. Once I do trust and decide I really like or love a person, I find it's rather easy for me to love them and work out issues where most people tend to give up if things get difficult.