What is the purpose of differently-sized stress boxes as opposed to flat stress or same-sized boxes?

Question

I can see the point of differently-sized Consequences on entities. Light ones are a mark, moderate ones are a more realistic, lasting dent, and so on. They behave differently and have, arguably, entirely different functionalities.

But what about stress boxes? Why would everything have not just differently-sized, but increasingly larger stress boxes? What is the reasoning behind PCs having

[1] [2] give or take [3] [4]

stress as opposed to just... 10 or a number of identical stress boxes:

[2] [2] [2]

Wouldn't it be easier to balance or create entities if, for example, small or frail creatures had X [1] stress boxes, whereas heavier ones had Y [3] stress boxes?

Answer 1

Fate is all about creating interesting stories. Progressive stress box values are designed to do exactly that.

The rules say that to absorb Stress, you have to mark off a box that has equal or bigger value than the number of shifts received. If you can't, you have to take a Consequence to reduce those shifts to a more manageable number.

This implies a couple of points:

1. If a character is struck by a particularly powerful attack, one that has more shifts than the target's biggest box value, he will have to take a consequence outright.
2. If a character is subject to numerous weak attacks, they will fill his Stress track quickly, because a single box can only absorb a single attack, regardless of its shift-value.
3. If a character invests into Physique, greater investment provides greater reward, making it an even more notable trait of the character. High Physique not only gives you more total shifts you could (potentially) absorb and more boxes, but also safeguards you from a one-hit-kill.
4. Because Stress works the same for every character (save for some imaginative Stunts), you can learn it just once. There are very few fiddly bits that change from encounter to encounter. Once you get past the original learning curve, you have an universal mechanic you can use anywhere.

To compare it with a game using your flat value suggestion:

1. Big, coordinated attacks are less important now, as any smartypants who can land (your_flat_rate)+1 will inflict a consequence. This results in less party cooperation and fewer awesome moments as well. Awesome moments are good.
2. Death of a Thousand Cuts is now less appealing, because you won't feel the huge, awesome satisfaction of checking a [4] box with a one shift attack.
3. Again, making tough characters would be less rewarding. Having [2][2][2][2] (8 total, 3 one-hit-consequence treshold) for Physique 4 is not as cool as having [1][2][3][4] (10 total, 5 treshold).
4. Now, we can probably agree that a flat rate would be just as easy as progressive rate, all in all. Progressive rate requires you to put in more effort learning the mechanics, but the flat rate will require more here-and-now attention and double checking if the value is appropriate. We can probably debate all day whether one is more elegant than the other.

To summarise let me just describe one more situation. In a low-stakes fights, standard mooks would have [2][2] instead of [1][2]. Not much difference, your houserule is unlikely to affect the encounter significantly. On the other hand, when the party fights a huge, powerful boss, a dragon perhaps, and you give him [3][3][3][3][3][3] instead of [1][2][3][4][5][6] it becomes much less epic, intimidating, rewarding and interesting.

But maybe you still don't like it

All of this said, Fate is also all about what works for you and your group. If you play some Fate games and decide you don't like the Stress tracks, you can ditch them completely, replace them with hitpoints, have only beefed-up consequences or deal damage to character's Fate Point pool. Whatever you like. If you find your group has less fun with progressive stress than without it, remember the Golden Rule.

Answer 2

1. You can only use one stress box per attack. This is designed to make conflicts more intense and quickly move players into taking consequences. Don't forget consequences are aspects which can then be invoked against the injured character/npc. Conflicts in FATE are ended decisively one way or another fast (in terms of exchanges).
2. Stress is not hit points that have to get worn down before you deal real damage. Stress is sort of like the effect of adrenaline at the start of a fight, it pumps you up and makes the first hit or so not seem so bad, but it's not meant to last. If a hit didn't force the player or enemy being hit to take a consequence, then narratively they shrugged that hit off.

The intended way to model toughness or frailness is with more or fewer consequences of different levels. Don't forget also that consequences are aspects which the players can then invoke

However, as mentioned above FATE is a toolkit. If you want to do several equal value stress boxes, give it a try. If I were doing that, I'd probably remove consequences though.