I've discovered something in Flare Empyrean which is so much fun that I would like to share it here:

1. Maximise the speed skill (by the way, why would someone not do that)
2. Get the escape boots from Kylana
3. Get at least 4 underworld Items excluding the boots

Now you have 3 ways how you can increase your sprint speed by 25%. Luckily this multiplies and your chara gets insane 96% faster sprinting! (1.25^3 = 1.96 ) (at least I think so. However, a 75% bonus is also great)

And this is where the fun begins... You can just run through the enemy lines, especially with the help of shield bash. Excellent for killing the same boss over and over again in order to gain the boss item.

Another fun fact: Usually shield bash can increase your movement speed, but the mentioned speed bonus here is so huge that you cannot see any speed bonus with shield bash anymore. It usefulness seems to be reduced to running "through" an enemy.