Why is theta negative?

Could you possibly elaborate on the concept of theta being negative? Could you explain what theta represents in the context of this discussion? I'm curious as to why it would be negative, and what implications this has in the realm of finance or cryptocurrency? Could you provide some examples or scenarios where theta being negative might occur, and what it signifies in those instances? It would be helpful if you could break it down in a way that's easy to understand for someone who's not deeply familiar with this subject matter.