I feel this way precisely because I keep doing new and novel things: there are so much to learn, think, and try out, I feel I am constantly in a rush.

When I was younger, I either have well-defined tasks or I would hit technical blocks forcing me to stop for a long time. Now, I get to work on all the hard problems to my heart's desire, and is also more skilled, thus hits way less blocks. I am in a constant race against my own ideas and desires to try new things...

It is cool and fulfilling, but also terribly exhausting most of the time :(