One of my sensei Stina Durell used to recite three guidelines at the start of every practise session with tanto for what to do if ever faced by some one with a knife:
1. Run away. Knives are sharp.
2. Do not try to do a technique. Just use your reflexes to try and do the right thing. Reflexes har faster than a thought.
3. You last choice is to try and anticipate what he will do and use an appropriate technique.
I belive that this is what you should do in any situation. I belive we practise to learn reflexes and a way of moving not to learn a technique.
I know many who have used their aikido in real life but not allways the fighting aspects. To know how to fall and regain balance is the most common usage so I don't think it's something I don't use in the "Real world" (tm)
As for dancing, I belive that my moves on the dancefloor has improved because of aikido