I, personally, hate it when the rules say that doing a certain thing (using a certain spell, activating a certain ability, whatever) is ALWAYS an evil act. For example, I recently made a Lawful Neutral Cleric of Wee Jas, in a group of Neutral good and Chaotic good characters. One of the other characters is a Cleric, and there came a point where the two of us were up against a Mummy, and both of us whipped out our Holy Symbols and did whatever we could against it- needless to say, we were 4th level, so it did nothing- but we wondered how the Good Cleric would feel about my Cleric after that. As you know, Neutral Clerics of Wee Jas Rebuke rather than Turn, so we looked up the Rebuking entry in the Player's Handbook- and what did it say?
"Rebuking undead is always an evil act."
...?! What the heck?! Why exactly is Rebuking Undead always an evil act? My character, for one, definitely isn't evil (in fact, he's been leaning more towards Lawful Good than anything else), and the only times he's Rebuked Undead it was so that his buddies could pound them easier. (And there was one time I controlled a couple Shadows to help us take out a baddie coming up, but I promptly killed them afterwards.) But, according to the PHB, that's always an evil act. Not only do they spend half a paragraph explaining Rebuking (whereas Turning gets half a page), they go and say it's always an evil act. I just don't get it.
Some could say it's because it's dealing with Negative Energy. Where, then, is the [Evil] Descriptor around the Inflict spells? They use negative energy a LOT more directly than Rebuking, and they're not evil. You could also say that it's because you're controlling Undead, and Undead are supposed to be the epitome of evil. Well, what about the Control Undead spell? Does the exact same thing, but it isn't [Evil] either.
Basically, I hate it when the game says something is ALWAYS an evil act. A sword can be used to kill innocents, destroy property, and frighten people out of their minds. But is using a sword to slay an evil dragon an evil act? Of course not. With a sword, it depends on how you use it to determine whether it's an evil act. It should be the same with Rebuking. If you command an army of undead to attack a village, sure, it'd be an evil act. But commanding two zombies to kill each other, so that your buddies can concentrate on the Lich in the corner, shouldn't be evil.