For example, I was riding my horse near Markarth when an Argonian bandit of sorts attacked me. I dismounted my horse, and slowly walked towards him. He preferred to send ice spikes my way, and there was no possible way for me to ever catch him, as encumbered as I was. So instead I raised Spellbreaker and just kept walking forward. His spells bounced right off Spellbreaker, thanks to my high shielding and enchantment abilities. He kept retreating and firing more, but I kept slowly advancing, patient as always. Finally, he found his back at a cliff, overlooking a raging river below. Seemingly, though perhaps it was my imagination, he became more desperate, firing off spells even more quickly than usual. And I just kept slowing advancing. Soon I was in flamethrower range. Then mace-range. Then finally shield range. Faced with the possibility of melee, the bandit whipped out dual daggers which he clanged uselessly on my impenetrable defenses. Suddenly my shield hit him, staggering him for just a moment. Just a moment long enough to see me drop my shield---finally, I was open---but not long enough for him to do anything about it.
FUS ROH DAH!
Heh, it's like you're an unstoppable juggernaut. Obviously its not great for most character builds, but it does make you feel like a total badass. More so than running all the time, anyway.
EDIT: Also, the shield tree has the best perks. Period.