dnd4

Most powers have one or more targets. Some common issues with targeting:

Many allies

Certain powers have a benefit that applies to allies. If taken to an extreme, a literal reading of the power would technically allow a cleric to use an area healing effect to help most of them.

As D&D is meant to handle small tactical play rather than clashing armies, powers should be limited to around eight people or targets rather than being able to handle entire groups. [RC:108]

Bag of Rats

Some powers have a beneficial effect on allies, including at-wills or encounter powers that provide healing or a transient benefit.

Such effects are only supposed to occur if there is a meaningful threat, as opposed to lugging around a bag of rats to exploit the healing at any time. [RC:108]