Many songs — often in Singer-songwriter and folk circles — have a Verse-Refrain structure or an AABA structure. This is when there are at least three verses with a short refrain, usually just a line, at the end of each verse. Storytelling songwriters (Bob Dylan, Billy Joel, Bruce Springsteen) like to use this a lot.
Using a bridge in these songs almost always works because these songs tend to be a bit repetitive. A bridge is the thing that breaks that repetitiveness and can also provide a bit of lift to the song.
A great example of this is The Beatles’ “We Can Work It Out.” The verses start with either “Try to see it my way” or “Think of what you’re saying.” One person is begging the other in the relationship to see the other side of things, to work with them to find a middle ground. The whole song is hopeful that everything will be okay, seen best in the refrain at the end of each verse: “We can work it out.”
Then there’s the bridge3:
Life is very short, and there’s no time
For fussing and fighting, my friend.
I have always thought that it’s a crime,
So I will ask you once again.
The lyrics are taking a different angle than the earlier “please see my side so we can work this out.” In the bridge, the lyrics have an attitude that’s more “c’mon we can’t keep going on like this — life is too short to be bickering all the time!”
The song actually goes Bridge-Refrain-Bridge, then back into two more Verse-Refrain sections, which is a variation on the typical Verse-Refrain-Bridge structure.
But you can see how the bridge added something to the song — musically and to the story. It doesn’t feel like an obligatory addition. It’s an important part of the song.