Here I am (at left) with some good friends and workout partners helping and cheering a fellow student at testing.

A fine picture of just a few of the many fellow students whose friendship and mutual support I will always cherish.

This was taken before our promotion test, so this is the last picture of those belts. By evening there were brand new belts with another stripe!

Bruce Lee said "Boards don’t hit back" — which made for a great movie line, but it ain’t quite so: Newton’s laws assure us that boards hit us back with a force equal to how hard we hit them. Fine as far as it goes, and not much help either. The trick ultimately is to do it fast and let the derivatives do work on the relatively inflexible materials we break while doing little or no damage to the highly flexible body structures we use to break with.
This esoteric description is neither necessary nor ultimately particularly helpful in actually breaking stuff — that’s purely about doing it, no matter what your brain tells you ;-).
Here are some samples of my breaking from my 3rd dan promotion [click’em to take a closer look].

This is one of the easiest hand techniques to get right — which this isn’t a very good example of 🙁 — because I just walked up and smacked it with little or no finesse. I can break three if I do it right, so sloppy was good enough for just the one.
Most newer students are awed/scared by breaking with knuckles, but it really is not all that bad so long as you go fast and don’t flinch at the point of contact. Again, only a single board, so no big deal. Two is a bit harder and requires good alignment to keep from skinning the hands and raising bruises. Three requires (of me at least) very good holders and some serious psych to get ‘er done.
This is an easy way to get a big pile of wood chips out of multiple boards so long as you nail the aim. Speed is easier to get out of the legs than it is the hands because the muscles are sooo much bigger and the distances you can reach significantly longer — V2 = 2*a*s really does work!
I do this one a bit different than most people because both big toes are so screwed up (from jambing them in tkd) that I have trouble getting them into the right position for breaking with the ball of the foot like is taught. I use the top of the foot, the instep, and have no problems breaking two boards this way. But speed is absolutely(!) critical.
The hilight of testing at all black belt ranks is concrete breaking. I have struggled with this off-and-on when required to do knifehand strike, but I have never failed to break with palm strike. The two breaks require radically different technique. Shown here are the three 8" by 16" concrete patio pavers still tumbling to the floor as I withdraw from the strike.

A certain amount of testing is just figuring out what you can make yourself do when you obviously can’t do anything more. To highten the tension, and thereby make everything more difficult, every test is different and the specifics of any challenges invented by the testing committee seemingly on the fly.
Case in point: Master Lim had already directed the 1st dan candidates to do 100 kicks and the 2nd dan folks 200 kicks so it is logical that for 3rd dan we should do 300 kicks. Here I am near the end of that ordeal gutting out the last of them. This picture catches me smiling — other moments might show more of a scowl, but I find the smile generally feels better.

Here are we all, another stripe to our names, some with one, some with two, and still others with three, but none of us anywhere even remotely close to the masters that tested us.

In the beginning, one can reasonably presume that the martial arts were intended as a means to train for martial purposes, aka, battle, but today, such a position is generally not founded.
This is not a "bad thing".
The role the arts play in today’s society could more correctly be described as a means to train to avoid battle in at least two respects.
First, the development and channeling of martial skill has a real tendency to satisfy an inherent need for combat and thereby divert it from venues less safe for such demonstration — bars being a common example.
Moreover, martial arts is far more than a physical skill. If this were not true, lifting weights is just as good. But on the contrary, training for combat, mock or otherwise, leads to a set of attitudes and a physical self carriage that repells would-be attackers.
Of course, neither of these effects is 100% in any case, nor is either effect even present in some cases, but on balance, our modern day training for unarmed combat will more often than not result in less actual combat, which is just fine by me, ’cause practice is way more safe than the real thing.