A few years ago I felt kinda lame whenever I had to "make a wish" blowing out birthday candles or whatnot and the only thing I could think of under pressure was "world peace".
Since then, I've kept a wish ready to blurt out if I ever see a falling star or toss a coin into a fountain etc
For me, it's sending my mind, with all my current knowledge and experience, back in time into my body at the moment I graduated high school, so I could re-live my life with more confidence, less anxiety and get straight into doing the cool bits of my life much earlier.
It's always been to fly. Every time I blow out birthday candles, every time I fix my necklace chain, every time I blow away a fallen eyelash, every time I've thrown a penny in a fountain (oh how I miss the mall fountain!).