Hope nobody is eating whilst reading this 
This thread reminds me of when I had to clear my mother's drains for her. She used to use toilet wipes, not wet wipes, actual wipes branded as flushable. TMI Alert:
Several years ago she rang me one day saying the toilet (downstairs one as upstairs was broken) had backed up. It would have been years since anyone had looked at the drains as she had lived alone for years.
So I popped round and opened the manhole nearest to the toilet. This was inside the garage, at the top end as the downstairs toilet backed on to the garage.
Now when you open a manhole/drain cover the actual sewer drain itself is a good 30 - 50cm below the cover. The first manhole was full to the brim of compacted shit, you could not see in to the drain at all, just pure poop.
I then lifted the second manhole cover, which is at the top of the driveway, about a metre outside the garage door. This was same as the first drain, full of poop just full to the brim and compacted together, that drain is deeper than the first.
Finally the third manhole cover which is at the bottom of the drive, yes you guessed it, full of poop, very close to the top and packed in solid, this drain is the deepest but was still nearly overflowing. When I say the drains were full, I bascially mean you could see no clay pipe, no brickwork, just shit.
So that was a full driveway plus a full garage lengths worth of built up poop.
And yes I cleared it for her. Wearing a face mask and using an old washing line pole I had to stir and stir it for hours until it started to loosen.
Quite possibly the worst day of my life.