We can let our past [difficulties and failures] beat us or teach us [to be more knowledgeable, competent and realistic in the future]!
Zig ZiglarYou'll never meet a happy ungrateful person, or an unhappy grateful person because gratitude and happiness go together. Sometimes happiness precedes gratitude but often gratitude precedes happiness. The latter is achieved by realising things could be worse but aren't and so feeling relieved, grateful and happy.
Zig Ziglar