Dreaming about a casino could be related to gambling, but "because you gambled yesterday" is too basic. Gaming can cause worries, enthusiasm, and deep-seated desires.
Remember that our minds' wide chasm doesnt merely make dreams from daily events. Sometimes its about going deeper and thinking about topics you're frightened to face awake. But lets just say "I played too much poker yesterday" and ignore it.
It's cool but maybe the person is just to consumed of what he was thinking all day. So when they got sleep, their subconscious would hunt them with the thing they truly want in their life. In short, be careful of what you are thinking or it will be manifested in your dreams, then in one's reality. That's how life works. It's alaways theperson creative imagination.