Per the excellent advice of Carlos Alejo, I've restructured this question to get more to the heart of what I'm seeking (thanks Carlos).
Is there any case in which the subjunctive mood can be used in simple sentences? And by simple, I mean sentences with only one verb and no relative clauses (neither present nor omitted). Or does a verb in the subjunctive mood always need a second verb in the indicative mood?
UPDATE: Well, yes, there is a case where the subjunctive mood can be used in a simple sentence.
Quisiera algo de agua, por favor. | I would like some water, please.
Can anyone think of any additional examples of using the subjunctive in simple sentences.