If there were no problems, most of us would be unemployed.
If you don't like your situation in life, don't fret or worry--do something about it. Worry less, and act more.
Forgiveness takes the burden of hate, guilt, and bitterness off your back and, with a lighter load, you can climb higher and faster, and be much happier in the process.
Sometimes adversity is what you need to face in order to [grow and] become successful. For that reason it makes sense to be grateful for adversities that help you grow, even if it is only in understanding and compassion for other's suffering.