Problems are not stop signs, they are guidelines.
Go for it now. The future is promised to no one.
Be kind whenever possible. It is always possible.
Always desire to learn something useful.
What you do today can improve all your tomorrows.
It's always too early to quit.
Things do not happen. Things are made to happen.
Only the educated are free.
The wise does at once what the fool does at last.
Know or listen to those who know.
In hard-core science fiction in which characters are responding to a change in environment, caused by nature or the universe or technology, what readers want to see is how people cope, and so the character are present to cope, or fail to cope.