using excessive punctuation and capitalization is not emotion
When I read informal text, CAPITALIZATION usually indicates yelling, screaming, laughing, or anything similar to that. sEMICAPS tends to indicate a sudden change in volume, or sometimes surprise. "Excessive punctuation" is just to indicate an extension of confusion (question marks) or excitement (exclamation marks).
In a medium in which you can't visualize someone's emotions under normal circumstances, people will find ways to better convey their feelings. Maybe the way people do it irks you. It's such a trivial thing to complain about though, but I guess I can't really stop you.