To me, the quality of the lyrics are usually a barometer of the quality of the song.
As a general rule, assuming a strong music writer, good lyrics will lead to good music, but, although there are plenty of exceptions, it's far less often that bad lyrics will lead to good music.
The test is whether the lyrics can stand on their own without the melody to accompany it.
Pink Floyd pre- and post- Roger Waters has always been an example of that.
So, yeah, lyrics are really important in music for this and other reasons mentioned above.
I agree, but...
... with that rationale, we wouldn't have the Beatles' Maxwell's Silver Hammer (sad lyrics/happy song) or David Bowie's Heroes (happy lyrics/sad song).