Proof of work is like starting a live stream, writing some viewer comments on a basketball, and trying to make full-court shots backwards. You keep trying until the ball gets in and once you make it, you number the ball and repeat the process with a new ball. Let's say everyone who got their comment on a ball sends some money to an escrow you can only spend after 100 balls are made after it.

Now if someone else comes into the stream while you're trying to get ball 64 in and does the same process of writing the comments and shooting backwards, then they can start stealing escrowed funds. For example, if they started from ball 63 and got ball 64 in, they would be entitled to the escrows for both balls (63 and 64). In that case the original person could focus on ball 65 and get a new escrow, or he can try his luck at overtaking the second person from ball 63 again.

In this example the balls are blocks, the comments are transactions, the miners are players, and the escrow is the combined fees and subsidy. Shooting balls is the equivalent of mining with sha256 and the winning block hash (with preimage) is like the video of the ball going in (the thing produced that shows you did the work).

I didn't add a difficulty adjustment in my analogy, but let's say when the commenters see too many balls get in the hoop too quickly, the commenters stop giving money until the basket is moved even farther from the players.