We made mistakes. (The active voice implies that the speaker is taking responsibility in a mature way.)

Norah Jones has been influenced by such musical legends as Ray Charles, Billie Holiday, and Johnny Cash. (The passive voice puts the emphasis on a single musician who was affected by the music of three different predecessors.)

The city’s new noise complaint hotline took numerous reports about loud music from bars and shouting neighbors. (The active voice puts the focus on the new hotline.)

An eight-year-old performed the violin solo. (The active voice is more taut and dramatic.)

In a patient with celiac disease, the body’s immunological response to gluten damages the intestine. (Perhaps because both versions are long and technical, neither seems significantly better.)