Last night I was playing and had a really hard brawl with an ancient dragon, had to use three dragonrends on it as it kept taking off, and used a couple of ultimate health potions as it was really hammering me. As soon as the soul was absorbed, and the guards had run up to gawk, one of them beside me turns to me and says: "Staying safe?"

casting a calm spell on a bad guy and then having them say " That spell didn't do anything." as they calmly walk off.

So I kill a bandit, go loot his things, but I accidentally take everything. So I drop half the stuff, when a bandit chief runs in and asks me if he can have the stuff I dropped. Which belongs to his fallen comrade. I found it quite amusing, so I humoured him and let him have it, where he said, "wow, really? This has got to be the best day I've had in a while!" He then proceeded to axe murder me. I legitimately felt bad about killing the poor guy. Regardless, I found it hilarious.

Not a reaction per se, but an NPC conversation between Danica Pure-Spring and Ahlam that I've heard in the Temple of Kynareth about Ahlam's husband. I won't spoil it.

Nazeem: Have you been to the cloud district lately, oh what am i saying, of cuz u dont.

Said to me when i was nearly at the porch of Dragonsreach.............

i swear if Wintersand Manor was available in skyrim, i will steal nazeem's key and wreck his mansion.

Well, I cant go into too much detail on this one, because it involves a quest.
So, a townsperson is looking for somebody who might want to earn some gold. I go do my part, but his cohorts betray me. So I go hunt him down in a cave. As I'm sneaking around fighting off the gang he has teamed up with, I hear him say "Come talk to me if you ever get bored." like he still wants my help. So after most of the gang is killed, he finally notices somethings wrong and while I'm still hidden in sneak mode says "I'm going to make you pay for this."

As a side note, despite my killing spree in this cave, a few of the bandits managed to find time to get some work done, like chopping wood and using a workbench. But, that made it easy to shoot them with my Glass Bow. Apparently, when somebody standing next to them takes arrow to the head, "it must have been my imagination."