Thanks for the insight.
In simple sentences, I can tell whether they are active or passive. The longer the sentence, the more apt I am to get confused.
I've written things that looked perfectly acceptable to me, only to have Word tell me after the fact that 25% of my sentences are passive, which certainly makes it seem as if I'm not paying enough attention to them.
Perhaps, as some suggest, I'm making a bigger deal of them than is necessary. Still, if I am going to go around breaking rules, I would prefer to have a firm grasp on what I am breaking and why.
Thanks for the input so far.