Not Gambling and Investment is risky, every field of business have risk. It is depend on us how could we earn from our business. But i agree with you, don't need to think for the best forever, when we can't achieve our purpose, than it hurt us. But earning wise i can't suggest do gambling, I know everyone agree on it, gambling has a full of risk. But take a chance to play gambling, if you feel you are lucky.
This is a serious venture in life as we take risk, hence we have to make a good decision all the time and do not expect you will not fail because it's normal when you are investing. I would choose to invest because it's been my dream to be rich and I have tried in gambling and did not like the result.