I just say, "At this time, I'm exploring a lot of options." Which is true, but then they just think I'm unemployed. I have a buddy (who's not a trader) that use to tell people when asked that question, "I'm going to school to be a rodeo clown." He'd get some funny looks and it turned out to be a great pick-up line.
Depends on whether you want to build attraction or not. Tell the truth = missed opportunity to create intrigue. Imaginative, funny, nonsense replies = attraction
A competitor came up with the 1/3 lb'er, cheaper than the 1/4 with more meat. Even though it was a better value, it failed. Most thought that the 1/4 had more since it was a 4 and not a 3 - true story.
I do this all the time: Cashier: "$43.62" I hand them $60 and instantly say: $16.38 Cashier: "Huh?" Me: "My change. $16.38." Cashier (in awe): "How did you do that?!" ---Like I'm friggin Houdini or something. If you want to really mess with em, give them the $0.62 after they entered the $60 in the register and say "just give me $17 back". It's like you just asked them to reprogram re-entry coordinates for the Space Shuttle.