stairway to heaven

[chaseback21969]

What is the true meaning of  "sometimes all of our thoughts are misgiven" 

[Carl]

I know this makes very little sense, but I thought the songbird from the previous line was singing that line to him. In other words, the tweets (the old-school kind) somehow formed that line in Mr. Plant's head:

In a tree by the brook
There's a songbird who sings
Sometimes all of our thoughts are misgiven

You see, the bird is trying to tell him something. Something deep.