Figure I'd post this in the spoiler section. I started the Dawnguard DLC, joined the Volkihar clan and was on my way to look for the Moth Priest with Serana. Along the way I stopped in Windhelm and visited Aventus Arentino's house while he was performing the black sacrament. After the dialogues came up I struck up a conversation with him about the whole Grelod thing. Anyway, I know that if Serana is with you she will interact with her environment (sitting in chair, workbench, grindstone, alchemy lab, etc). As Im talking to Aventus I look in the background where he has the skeletal remains and candles and what do I see? Serana on her knees, ( I thought she was going to perform the black sacramant) pulling out her elven dagger and starts to stab the skeleton! I was like WTF?!

Anyway, this got me thinking. Id like to hear some of your out of the ordinary Serana interacting with the environment stories.

Just the regular things like you mentioned.

She was frozen once in the Soul Cairn. It was extremely annoying.

honestly that was awesome but i don′t have many stories she is all cool with me and never does anything wrong of course once in a while she resurrects a dead chicken but HEY! maybe she just wants her conjuration skill to raise i don′t really censure her.

As I understand it, Serana is set to be able to use any 'behavior markers' (I don't know what the actual term is) that are in the area she's in. The stabbing the body thing is actually set up for Aventus (if you stay back a bit and watch him before talking to him, you'll see him stabbing the skeleton himself), but because he's gotten up to talk to you, the marker is now unoccupied, so Serana takes over and starts behaving according to the behavior the marker dictates.

Now, the question is where there might be other unique 'behavior markers' that she can use, but I can't think of any off the top of my head. Maybe if you hang around the Castle Volkihar dining room, she starts feeding on the Human Cattle there because there are markers for the other vampires. It would be kind of amusing to be playing through the Dawnguard side of the questline, be assaulting the castle in the final offensive, and have her stop for a 'meal break'.

Maybe she wanted her father dead and was hoping she could enlist the DB's help. But no JK I've seen her cower in fear at Molag Bals shrine and pray to various Gods like Mara and pray in the Gray Beards place.

Well one of the other ones i've seen is that she does the prayer motions that the Greybeards normally do when you're at High Hrothgar.

for me she has-
Released Odahviing from the trap
relaxed in the hotspring while wearing forsworn armour
sat looking like she is dying where the dying synod mage is when you first enter the dwemer ruin (CoW questline)
used the skyforge during Kodlaks funeral
meditated in High horthgar
Sat in Balgruufs throne

I'd have paid to see that!

That's awesome, thanks.

Had her use the forge in Riverwood and I swore I heard Alvor tell her "Thats a fine piece of steel there" or something he and other smiths can be programmed to say when your smithing something.

I've had her dance drunkenly to my bard singing horribly in Windstad Manor.

Also outside Moss mother cavern when Valdr gets a healing potion and stands up Serana will do the wounded soldier stance on the ground.

She did that one time as well. My bard in Lakeview started singing, Jordis(wife) and Lydia(steward) started drinking and dancing, Serana walked over and joined them. Pretty funny stuff.

I know it adds depth/realism etc but I wish she wouldn't interact with the environment myself as she will always end up in my way, either using a grindstone/workbench that I'm just about to use when I'm upgrading equipment, or mining ore veins that I haven't done yet. If the ore was actually collected that would be great and save a bunch of time, but its not, so its a pain.