The prayers in Judaism are highly regulated. The direction which a person stands, the time for prayer, the preceding praise to G-d before asking for one's needs, etc.

There are pros and cons for structuring prayer. If prayers were spoken spontaneously instead of at fixed times, it would be inspired, it might be with more proper preparation, and people wouldn't have to pray in difficult places like airplanes.

There are important advantages to structuring prayer, though. It is easier to find a quorum. People pray even though they might not have prayed at all, giving them consistency in turning to G-d regularly. And by preceding praise before asking requests, a person has more respect for G-d.

Adapted from R. Sokol's Gemara shiur 2/27/99