The Subtle Disruption of Disparate Magical Styles

Another hoofnote. I think I'll call them that from now on. You know, in keeping with the whole pony thing.

When Twilight and Colgate are trying to push the collapsing wall back, why is it that Colgate's magic is said to get in Twilight's way? Celestia talks about what magic is a little bit near the beginning, but here's a concise definition: magic is a manifestation of willpower in the physical and, with more advanced magic, metaphysical world. Different ponies have different styles of magic, just like they can have different thinking styles, different personalities, et cetera, and not all of them mix well.

Here's an example. Twilight's a pretty methodical, meticulous pony, and the way she casts spells follows that paradigm pretty well. She's good at telekinesis and altering forms, both of which require intense concentration and technical knowledge, but she would have a hard time with something more chaotic or relaxed, like conjuring a storm or mind reading. On the other hand (hoof, whatever), Colgate casts spells more passively, relying on suggestion and the steady application of force. Her magic would be better for dissolving something or subtly cheering someone up. If Twilight's magic is like taking a problem apart with tools and precision, Colgate's magic is like studying it and tweaking it.

On a completely different note, what kind of parents name their child Ditzy Doo? Seems kind of mean.