Yes like me. This things happen don't worry. It is just frustrating reverting wrong edits by some users (don't worry it's not a blame). Just read categories before being sure adding them. You can even ask an admin or justifiy yourself when not sure.
Blazing, one thing that can help out is don't add just categories. Work on adding more substance to the main part of the page.
What I've found is the people who spend most or all of their time adding categories wind up creating more of a mess than helping to organize the page because they start putting in categories that are really trivial or definitely don't fit the page. They use categories and/or begin stuffing factoid after factoid into the Infobox as an excuse not to write anything on the main part of the page. For example, they don't bother describing how Rodney McKay from the Stargate TV shows is arrogant because all they have to do is add an "Arrogant" category or add it to his personality section of the Infobox.
When you're considering adding a category, flip it around and ask yourself, "Do I really think that when people come to this wiki, they specifically want to know what characters are in this category?" If the answer is no or probably not, then skip it.