One large criticism of multiplayer games, especially when online and relatively anonymous, is that players can be harassed, trolled, and griefed oftentimes with little recourse available in perspective to what was lost (for example, losing a game and as a result having a lower rank in multiplayer or losing many hours of work). This can be alleviated by removing the potential negative impacts other players can have on a single player. This is not necessarily applicable to all types of multiplayer games but can work well with games where the single-player experience (if any) is very similar in design to the multiplayer experience.
Journey is a good example of a game where multiplayer can only help and not harm the player. The single and multiplayer experiences in Journey consist of traversing the same levels, the only difference is that in a multiplayer experience another player may be in the same level as the player. The other player can do nothing to impede the progress of the player, however, the players can help each other move through the level more quickly than if one player was traversing it alone.