You don't have to chill, just be respectful. Be passionate. I am always interested in vigorous debate. And as jebrick has mentioned, I can compromise. Most of the players here didn't see the ritual spell issue the way you and I do, for example. I honestly think my interpretation is RAW, so we have an impasse, and may need an HR to clarify things.
Sure every PC/NPC has limits, and I operate within those limits much as anyone else. When players impose limits: I work to make sure that they're clear on them (see my comments about the casting token issue that has developed). So yes, I work within limits and I work to exploit those limits to the extent possible, much like players do.
I share some of your same views regarding mastered spells and the desire to avoid spontaneous spells. Flawless Magic, in my view is the single most powerful Hermetic Virtue in the game. It's the gift that keeps on giving. I have some issues with the overall XP sink of spell mastery and also find that there is a problem with multiple casting (I think it is unreasonable that you can cast X extra copies by only buying multiple casting once). I think we're going to try this mastery HR in Via Experimenta. I'm not going to recommend it here... it's too untested.
In any event, I do admit that mine is a very strict/conservative reading of the rule for fast casting. I tend to go that way with a lot of things. I can always relax a previous ruling or understanding later, but it is much harder to take back a ruling later. At this time, I'm still not inclined to relax my understanding, but if everyone says they can live with it, I can live with it. For example, under your understanding, in Andorra, could someone have acted, by way of fast casting, at initiative point 13 and destroyed the waiter before the bomb went off? Because that's exactly what I see as being possible under your proposed understanding.
What I hope you and anyone else gets out of this discussion is that my understanding, and yours is a well considered understanding, and each choice has a significant impact on the saga, and how some things become possible.
And I would generally prefer that players do exactly what you suggest you're doing...