I don't get Ultimecia.

She calls Seifer a "worthless child" and "useless fool" but continues to have him lead her every major campaign or activity. If he's so utterly Fail to her you'd think she'd fins omeone else.

Perhaps she was just pissed at those specific moments because Seifer lost, but in the end she knows that he is probably the best qualified guy in Galbadia to carry out her plans, plus it's hard to find another guy who can be influenced so easily but at the same time as the streght of Seifer.

Ultimecia probably wanted Squall as her knight instead, but since he didn't have any ambitions that she could use to manipulate him, Seifer was the next best choice.

This.

Ultimecia is nothing more than a 100% generic, apathetic antagonist who has the approximate depth of a tea cup. Probably less. She's the type of villain who will constantly kick everyone around her despite relying on them for basically ever single aspect of her master plan. She's willing to crush, destroy, and belittle anything and everything regardless of whose side it's on. Because they're her minions, they definitely won't betray or abandon her or anything like that. Heavens, no. Ultimecia is the primary antagonist and, as such, commands the total respect of all of her minions for absolutely no good reason.

Seriously, Ultimecia is just one angry little puppy, kind of like every other 2-Dimensional, psychotic villain before her. She falls into the all-too-disappointing cliche of "Acts mean to everyone without regards to the potential consequences." Remember those old 1930's cartoons? Remember how the villains (the ones with the mustaches and top hats) would act mean to his two little stooges, yet they would continue to follow him around like sick puppies? Well, that's Ultimecia.

I'd consider the possibility that she is aware of Seifer's excessively competitive nature - and considering the fact Squall is effectively 'leading' the opposition to Seifer's forces - and thus used it to her advantage. Genericism aside, she's evidently manipulative, leading to the possibility of her using Seifer's aggression, as opposed to simply undermining him for the sake of... well, undermining him.

Not a great villain by any means, but I don't think she was entirely simple.

We also have to remember that we have no way of discovering Ultimecia's drive; she exists so far in the future that even if we wanted to, we have no idea what she's been through. We don't even know what her future is like, because we only see it after it's been squished by pseudo-time compression. Just keep that in mind when you are complaining about her being 2-D... she could have had completely different plans and ideals than what we thought, but we only get to see a small sliver of them due to the framing of the story.

Ultimecia didnt really need Seifer all that much, she calls him useless for failing on her but she could have acheived time compression without him.