I don't have any horror stories but...
OK, in the interests of sharing information I'll confess I do have a horror story.
I don't know what experience others have had with well diggers but on one parcela I later sold, which was at the top of a hill, the well wasn't deep enough so eventually we had to sink deep pipes. The original well had no support on the inner walls but was capped with concrete. The mix of rock and soil help up very strongly no problems but it just wasn't deep enough.
The horror story started when I moved to a hillside consisting of deep red clay. The constructor said that he would dig a well with his jcb excavator. In order to get deep enough he carved a huge ramp into the flat bit of hillside just below our property and was able to hit water ten meters. He finished, leaving a long down-sloping scar across the property with a deeper hole at the end of it. To near the edge of it was to experience vertigo and raised some safety concerns. He said not to worry and we could take our time with installing a lining (pipes) and then he would come back and fill the scar in around them. He claimed that it was a tried and tested method, no worries.
But then the rains came and filled the entire long depression with water-almost to the top. No worries he said-just wait for the water to drain off. So after a couple of days we hear gigantic sploshing noises from downhill during the night. Seems this type of clay soil doesn't hold up when wet. Within a day or so the side started to cave in and more worryingly, fissures were radiating (arcing) out from the original edge. The land between these cracks and the original 'shore-line' then collapsed into the hole and two more fissures appeared which also collapsed. I looked up at the house and shuddered as I imagined the fissures advancing up the hillside.
The next day we got another excavator - having lost faith in the first company to fill in the entire lake and it did take all day. Now I got a flat area below the house - compacted, with no further movement.
Our neighbor went with traditional hand dug well but that also totally collapsed under the heavy deluge we had last June.
So - beware of well diggers. Yes I know you need that water but think on it !