Visualization of Magic {Discussion}

I’m not sure if this has been discussed before on this subreddit but how exactly does Visualizing the effects of your magic wind up as the desired outcome?

I know the question phrasing is weird but how does Ubel for example possess a basic cutting magic but can visualize being able to cut through anything using it? If it’s all a visualization game why can’t someone just use a fireball and think it’ll melt through anything it touches and just burn though a defense magic?

Or inversely how come no mage thinks “my barrier is a shield and shields block things so it’ll block anything” and just has an unbreakable shield that can withstand 1 million Zoltraaks? Why can some people break through defense magic when the one casting it very clearly visualizes blocking attacks with it? Maybe I’m thinking too hard but it’s just a 3am thought that has me thinking while looking at the ceiling…

I’m not trying to get definitive answers I guess but I’d like to hear what you guys think