Question: My character is a bitch. Freeze Out fits her perfectly but she would never dream of being anyones BFF or giving them a Blessing of Importance. Peak Performance fits her perfectly because she likes to shut other people down, but she just doesn't care about having Theme Music. Why are these things prerequisites?
Aww, anonymous - don't take those knack names too literally! One of the great things about Epic Charisma is that it takes different forms for different people, which means their knacks are always flavored differently as well. Those knack trees are together because they're conceptually related, but you should never feel like you need to use a knack the same way someone else might. That's what stunting and description are for.
The Blessing of Importance/BFF/Freeze Out/Believe Your Own Press tree is about your opinion being the most important one in the room, because that's just how badass your Charisma is. Those knacks go together because they all hinge on the force of your opinion and personality Making Things Happen around you; after all, if your opinion doesn't even carry enough weight to make a single person change their outlook with Blessing of Importance, how can you expect it to affect everybody with Freeze Out?
Similarly, the Hapless Cool/Theme Music/Peak Performance tree is about your mere presence being so inspiring and incredible that it changes how everyone around you thinks. Those knacks are about being so noticeable for those around you that just being around impresses, intimidates or impacts them. Your presence in the room, with those knacks, always makes a difference when it comes to how people react and respond to you and what you do.
That's why those knacks are together, and we like them there and aren't likely to change them because of it. But there's good news: as I said above, the name of the knack doesn't really mean anything when it comes to your character and how you choose for her Epic Charisma to be represented. Epic Charisma doesn't always mean happy sunshine cuddletimes; obviously you know that, since your bitchy character has some in the first place. What Epic Charisma means is having a powerful, forceful presence, and while for many characters that means being likable, charming and fun to be around, it can just as easily mean being commanding, frightening, forceful or intimidating. A good real-world example might be a powerful military commander; the fact that perhaps nobody in the room likes him doesn't in the slightest change the fact that when he says jump, everybody in the room is in the air before they've had more to do than subconsciously register his intimidating presence.
With that in mind, every knack can pretty much be used to work with your personal brand of Epic Charisma. So you're not anybody's best friend - so what? You can still use Blessing of Importance or BFF without making your target feel particularly good about it. Instead of making them feel like all's right with the world, perhaps your character refills Willpower by motivating them to get moving again or risk her displeasure, or by setting such an awesome example of iron-hard will that they can't help but try to emulate her. (We recently had a post that dealt specifically with one of our characters using Epic Charisma in just such a non-cuddly fashion, in fact.) It may not be your character's mission in life to make people feel good about themselves, but she would probably like them to be more effective in doing what she wants, so filling up their Willpower is just pragmatism.
Theme music is a more difficult proposition; I feel you there, because not every player really wants their own theme song, as much as some players love it to pieces. I'd keep in mind, however, that having Theme Music doesn't mean you have to be charging into battle to the dulcet strains of Maroon 5; choosing something simple, instrumental or evocative of your character's personality - even just a steady drumbeat - can still enhance your character's capabilities without being distracting or even coming out of the background much. (You can, of course, always opt not to do anything with your Theme Music as well, but I'm always a bigger fan of finding a way for a character's powers to work for them rather than discarding them.)
While you should pay attention to the mechanics and intent behind knacks, monkeying with their flavor text for the sake of stunting is one of the great traditions of Scion, especially when it comes to social powers. As long as what you're stunting makes sense for your character and doesn't change the way the power itself works, there's no reason at all you shouldn't be able to stunt your Epic Charisma knacks in such a way that they suit your character's personality.