It's tough work to carry someone else's weight, it's not like people arent also busy with work, starting a family, and other things. And then you watch a lot of people almost "worship" the person, and animosity builds. I'm not saying its right, but it is a valid human emotion. And my experience says that humans are emotional creatures.
Up until about 6 months ago, I still had a major grudge against a former mission companion. I grew up and decided what happened years ago wasn't going to effect me. However I still think my emotions were valid in that I had reason to be upset. The issue is letting it control us, it's a process and sometimes people need to vent. I hope you can understand that, it's human nature.