I'm always talking to God about whether or not he exists - that's how I know I'm a theist.
Everyone has a sense of humor. If you don't laugh at jokes, you probably laugh at opinions.
For God to prove himself on demand, physically, would be a grave disappointment, and the strongest Christians should be considerably grateful that he chooses not to do so. The skeptic endlessly demands proof, yet God refuses to insult the true intelligence of man, the '6th sense', the chief quality, the acumen which distinguishes man from the rest of creation, faith.