A lot of us are very hard on ourselves, and unforgiving. There's nothing worse than knowing we blew a big opportunity, or brought a great loss into our lives. Some cultures and philosophies blame you for your bad luck; and make no mistake, luck is a powerful life factor.
It's really easy to fall into the trap of thinking we're not worthy or perfect or good enough to be doing God's work. Because we're human we make mistakes and blunders. The issue, though, is the magnitude of our mistakes. If we get the big things right - such as remaining faithful to God - the other things pale in significance. We make many decisions every day and some have moral significance, but don't worry if you discover you were wrong about one or another. Perfection isn't possible in this world; though it is a worthy thing to strive for. Think of life as a craftsman would. Try to do your best, but know there is always room to improve. It's the effort and heart that count.
The truth is we don't really have certain knowledge of what God wants from us. Scripture and our conscience say we must be loving, kind, and generous, but those are only general qualities. For example, what is love? Is it the feeling of elation and affection that comes and goes? Love must be more than that, and it is. The love God wants from us is actually expressed as 'steadfast loyalty', which means that through thick and thin, pain and pleasure, wealth or poverty, we remain faithful to God and believe in God's goodness. It's not easy to do that, but it's the most important thing we do in this life.