Three dices are thrown simultaneously.
You can bet $1 on a single number, 1 to 6.
The odds are rightly 1/2 so you get $1 for every occurrence
of your number. Of course you get $2 or $3 for double or triple
occurrence.

After 1000 throws you won $500 betting always on the same number. Even game?
Wrong! You lost money, considerably.

Here is what happened:

There was 355 throws with only one of your numbers shown.
68 throws with doubles.
3 times you got triples.

This makes $500 in total, but made in 426 throws.
The rest of 574 you lost $1 for each throw, which makes -$74.

This is a regular pattern, proved in many simulations.

Nice one, isn't it?