1. I would like more buoyancy, in general. No real interest in flying, but I think it would be great if we could really rebound out of movement and get some gravity defying air time in the process.

2. What if some sort of activation color, light, or button appeared on you when your body was doing major work on it's own, like fighting a disease, reproducing cells, regenerating tissue, or creating a baby? That would be cool.

Ooh! I love #2. What if our expended heat was part of the visible light spectrum. IR as color palette, maybe that's a worn out area though. Heat remnants, heat tracks, heat signatures.

'You have been activated" brings to mind a positive spin on the Manchurian Candidate. What if activation happens when you have amassed a certain amount of kindness credits, or interspecies collaboration? And at the moment of activation, you have the power to bring to fruition any thought (or three) you have had in the past hour. You know activation has occurred because you see a screen in front of you that lists all your thoughts. You get a day to choose one (or three). From other people's perspective, you just disappear from the visible spectrum. For a day, you are pure energy and you can Make Things Happen. The Berlin wall falls. People land on the moon. Somehow you discover activation. How do you live your life?

Not so hot on #1 to be honest, but Love #2: intriguing idea! Perhaps not everyone would see the "extra heat" given off? Maybe it's not a visible color, but an out of spectrum frequency (sort of the opposite of what @Tod Robbins was suggesting).. people with the ability of seeing this frequency might be sought-after from (ill- or well-meaning) organizations to spot and monitor this activity...

Monitor a political opponent during a debate or deposition for stress... or monitor for signs of this sort of activity.. maybe a certain pattern indicates a spreading illness..

Not **exactly** what you're looking for in your second imagining, but the work of Daisy Ginsberg in synthetic biology is a move in that direction, specifically her E. chromi project.

I like the idea of activation colours and/or glowing...but being a control enthusiast, it would be great if it was controllable. Why? Because I like to go to the movies.
I like the idea of bouyancy but I'd like to have it be caused by clothing you can don. Padded clothing.
: )

I would actually like uncontrolled activation colours. :) I'd like to see what consequences it would have: would people be able to block its emission with special pieces of clothing? Or would everyone don de-activation glasses when you go out in public that dims the colours to a manageable level, but then regular colours are also dimmed (like cheap sunglasses)?