Hmm. I suppose I should say they are not complicated in terms of contemplating complex formulae and so forth. There are, of course, spells that require that, and if you wish to write a spell down so that others can learn it, the process is often quite complicated.

The truth is, most pony spells are developed intuitively by those whose talent suits the spell, and it is difficult to describe or translate them to those who do not have the knack. Teleportation, for example, is a powerful magic that takes a great amount of natural ability to perform, and I do not know if anypony has ever managed to successfully write a general all-purpose teleportation spell.