Hmm. In public, i'm most likely shopping. For me look in the make-up aisle, shoes aisle, clothes aisle, jewelry aisle. Sounds vain, but i'm usually just browsing. I enjoy seeing what's new, and what's better.
ENFPs are usually the ones that have a confused look on their face - Or, content. You may detect a hint of amusement, sometimes seemingly at nothing at all. I'll smile at things I think are funny, and occasionally laugh, even if there is no one around to share the humor.
I'm quite 'floaty'. I'll go from looking at one thing, to looking at another, and then back to that one thing, and then to a completely different aisle.. And then back to that one thing.
I'll grab things from shelves, look them over thoroughly, and then put them back. Sometimes I will carry them with me for a while, and put them back where they don't belong because i'm too lazy to put them where they DO belong.
Otherwise, if I'm not shopping
Look for the zany ones. The ones that dress and act differently - the ones that especially seem to have 'something up'. I personally don't care what people think. I'll talk to myself out loud, sing the tunes that won't get out of my head, and yell for my friends if I don't know where they are.
And look for the especially animate ones.
That's all I can really say. Enjoy my big bunch of ramble, which probably didn't help much at all. But I'm sure there are other ENFPs that can connect with this.