The imperative command can be made forceful with the use of an exclamation mark, or the mark can be left out and the word "please" added to make it a softer command. Imperative commands are not usually acceptable for academic writing, however. Imperative voice is usually acceptable in some circumstances, such as the following sentence: "Consider the following evidence."
In informal writing, imperative commands are commonly used, but they should be limited, otherwise they start to lose impact. It's difficult to show that a character is shouting if imperatives and exclamation marks are routinely used.Learn more about Writing