I had liked Sondheim a good deal when American Musical Theater was still in my blood. I particularly liked the story that as he was writing lyrics for "West Side Story" and Bernstein wasn't finding his efforts quite right that he decided to do the cheesiest, most over-the-top lyrics for "Tonight," just to show Bernstein what dangerous road he was head down...and Leonard wept, saying "this is exactly what I was looking for." So Sondheim knew what he needed to do for the rest of WSS. When I first heard this I had done the show myself only a few years before (I played Action, who disappeared in the movie, but is a big deal in the play) and was a touch offended, as I liked the lyrics to that and other numbers from the show quite a bit. I still chuckle over I like the island Manhattan...Smoke on your pipe and put THAT IN! from the cynical Puerto Rican character played by Rita Moreno in the song "America." Yet I gradually came to see the point. It's a bit much.
But when I did tech for "A Funny Thing Happened on the Way to the Forum" and my best friends and a girl I had a crush on were in that production (Glenn Close was not, that time) I was still thrilled at the wordplay. I grant that it is from an older era, the Cole Porter/Noel Coward style where the internal rhyme and surprisingly topical references kept escalating in a "hold my beer" fashion, so that the naive Porter put Mussolini in "You're the Top" until his friends insisted he had to take that out. But still, it's fun.
Not until I went to a summer theater production of "Into the Woods" 10-15 years ago did I feel I had eaten too much candy. My brother was doing lights, when I mentioned after the show that I thought the lyrics were a bit much he nodded and said that Sondheim was "showing" off by making a sexual gesture, if you catch my drift. I thought that was apt. Yet even in that show, there was much that was good. He did some later shows, which I know nothing about, so I don't know if he continued down that road he sneered at Bernstein for fifty years earlier.
That one negative was powerful enough that was anti-Sondheim until quite recently. Yet that is unfair. He was immensely clever, far better than I could pretend to be for even a single verse, and if he got a bit full of himself at times, well, so did Porter and Coward.
So this is where he lost control, perhaps, and if you are going to hate him, you might start here. Certainly, the repeated Into the woods! Into the woods! Into the woods! is hard to sit through. But I think on balance even here you will find it remarkable.