It's always too early to quit.
Problems are not stop signs, they are guidelines.
If you're going through hell, keep going.
What you do today can improve all your tomorrows.
If you've got a talent, protect it.
Know or listen to those who know.
Only the educated are free.
Begin to be now what you will be hereafter.
Things do not happen. Things are made to happen.
To know oneself, one should assert oneself.
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.