After a bad 20 minute session like I just had, I'd really like to go back and see what I missed, and maybe even drill some of these troublesome words that I keep missing or getting "so-so" into my noggin a little deeper.

I'd like to have an exportable list of trouble words that I could review offline. Preferrably, a the list would populate itself during each session every time I hit the red "1" or yellow "2," be available for export for 24 hours, then reset itself for the next day.

Bad idea?

Often, the words you have trouble with one day are the words that fall into place the next day. Memory is funny like that - or learning is. Immediate extra drilling is not always productive especially if you are frustrated. Emotions affect learning and memory.
You can look at the words in your vocabulary list and see which ones you haven't learned well yet. If your retention rate usually hangs out around 80%, I wouldn't worry. If you have a quiz coming up, try an alternate method.
Sometimes I draw a picture with stick figure people and use the stubborn vocabulary to label or describe it or create silly dialogues. It relaxes me, makes me laugh and usually breaks the brain lock. I just did that and had a giggle explaining my art to my husband.
Try Yellow Bridge - they have flash cards and a memory game which make a nice break and will still stoke the memory.
I'm a teacher by trade and still bang my head against the wall sometimes before I remind myself of what I have written above.
Good luck and may the Farce be with you.

@jcdoss, I know the feeling but being frustrated is just as Granuaille says, contra productive. If you like to have a list of your troublesome words, use the export function and choose to have it listed in least known order. Then you get your most troublesome words. I use this and run it in a homemade program to create voice files from them with Chinese and English. This file i use in my player when running. I also do like granuaille and do silly things with them. In my case i use the words when trying to tell the bed stories to my 2 daughters. They love to make fun of poor old dads poor Chinese. To have fun when studying is for me one of the key components. Relax, get away from the study, try to use the word/character in other context etc. Just do it differently. At the university in China in the 90:th i had a young teacher that took all our troublesome words and wrote them on paper. Then each of us got one of those and had to play charades with that character. I still remember several of those characters just because they where so crazy. Same with silly mnemonics, the more crazy the better. They will stick. I had e.g problems with the character for Germany 德. My mnemonic for that is " It takes 10 steps and one net to catch a German girls heart". That is stupid enough for my brain to remember.

You can mark the characters or words you get wrong manually with a star, then drill them from the bottom of the practice page later.

@Byzanti I just tried what you said, but the words that I star-clicked didn't show up in the scratchpad area of my practice navigation page

@Byzanti Okay, nevermind, I found it. Thanks!
If anyone else is interested, it's on the very very bottom of the practice navigation page, below the scratchpad area. It's called "Starred Words"

haha, now I have a different question about this. I just went through my queue and starred some words, and then went and crammed my starred words list. After I was finished doing that , I noticed that the list is gone. It's not on the bottom of the practice navigation page anymore. What happened to it?

I was hoping while I was going through the starred words list , that once I felt pretty comfortable with any of the words in the list, I could click on the yellow star , so that they would be taken off my starred-words list. But now the entire list is gone, haha :(

Have you cleared all the words from being starred? There is actually no list as i know of. It is just a marker for the word/character. If all of them are cleared there will be nothing down there. If you star a new word/character it will show up again. I use this a lot and it is very helpful. I actually keeps me words in the star list for at least a few weeks until i feel very confident that i know them. I should trust the algorithm but in this case i need the extra boost for my memory and just quickly go though the words every now and then.

okay, I saved a few more words and now the list is back. Maybe there's a minimum # of characters/words that have to be starred for the list to appear