This is the problem on what majority of the people feel since they view gambling as an activity of earning money. Sure, you can double your money tonight but it also carries the risk of losing everything at once.
If you gamble with a mindset of doubling the money, there is a high chance that you will not play responsibly and at some point, there will be an element of greed and emotions in your game. In order to play responsibly, you should lower your expectations from gambling. There is nothing wrong to expect to win and gain money from gambling, but making 2x overnight is not the realistic approach.