Regret of neglected ...

Regret of neglected opportunity is the worst hell that a living soul can inhabit.
Regret of neglected opportunity is the worst hell that a living soul can inhabit.
 Rafael Sabatini

More phrases

We are in a survival mentality, and that's hard-wired into our humanity, because we are the winners of an evolutionary struggle of millions and millions and millions of years.
 John Shelby Spong
There is an ocean of endless opportunities, and there are so many things that one can do. I'm so fortunate that I've grown up with this sort of a philosophy and mentality.
 Hafez Nazeri
I like to challenge hitters with a 'Here it is, hit it,' mentality. It's definitely a big part of my game, especially when I get in situations where I need it. I usually save a little bit so it's there for me.
 Justin Verlander
Sala-manda-stron, look out here we come, A thief a warrior and a mole. Though the quest may take its toll, We'll march until we reach our goal,
 Brian Jacques
A warrior takes his lot, whatever it may be, and accepts it in ultimate humbleness. He accepts in humbleness what he is, not as a grounds for regret but as a living challenge.

Quotes from the same author

In endeavor itself there is a certain dynamic entertainment, affording an illusion of useful purpose. With achievement the illusion is dispelled. Man's greatest accomplishment is to produce change. The only good in life is study, because study is an endeavor that never reaches fulfillment. It busies a man to the end of his days, and it aims at the only true reality in all this world of shams and deceits.
 Rafael Sabatini
But I like my madness. There is a thrill in it unknown to such sanity as yours. ~ Book 1, Chapter 9.
 Rafael Sabatini