Definition of EV0
EV0 or neutral EV is a game in poker that, in the long run, will neither make nor lose money. The classic example of the EV0 game is the coin toss. Let's say you and I bet 10 euros per round. Then we toss a coin. Every time it comes up heads, I get 10 euros. Every time it's heads, I owe you 10 euros. In the long run, our expectation of winning is 0 since our equity will always be 50%.
EV0 games, difficult to identify in poker
In the coin toss game, it is very clear and obvious that the EV is neutral in this game. But in poker, these types of games are more difficult to identify. Everyone can easily identify an EV+ play, an EV- play, but few can name the EV0 plays. Some bluffs on the river are EV0. Whether you bluff on the river or not, sometimes it won't matter. But we can consider this. If a situation is EV0 and you have two options (to bluff or not to bluff), if you always choose the aggressive option, your image at the table will be different than if you always choose the passive option. This is a detail to consider.