Go for it now. The future is promised to no one.
Well done is better than well said.
I can, therefore I am.
It's always too early to quit.
Things do not happen. Things are made to happen.
The wise does at once what the fool does at last.
If you can dream it, you can do it.
Either you run the day or the day runs you.
You never know what motivates you.
If you're going through hell, keep going.
Soon I knew the craft of experimental physics was beyond me - it was the sublime quality of patience - patience in accumulating data, patience with recalcitrant equipment - which I sadly lacked.