Fusion spells aren't complicated, but the temporary ponies they yield are. Speed Reader isn't thrilled to be made of the two most high strung ponies in Equestria, but surely she can keep her selves together for a measly half hour, right?
Routine day with a dirt cheap brush, then a week goes by and it goes untouched. Then two, then three, then a month, and the rest of your life you beat yourself up. - Aesop Rock, "Rings"