I was on holiday in the UK a couple of years ago, down in south west, and it insisted on sending us down these really narrow, single-car-width country roads (with passing places). I grew up in the UK, and learned to drive on them, so no particular fuss with actually driving down them. The problem is they're "National Speed Limit" roads (60mph / 30mph in built up areas). They're just too narrow, and too twisty, to be able to come even close to it, let alone do it safely.
Unless there has been enough cars using Google Maps going down that road, within a recent enough time period so that it knows the road is currently slow, it'll send you down it assuming you're able to go at something approximating the limit. Sod the large road that's just a little bit further away and legitimately can be used at those speeds. It got almost farcical. I'd even attempt to persuade it otherwise, and part way through it would reroute and I'd still end up going down one.
google sent us on a fire road cut into the side of a cliff over a small stream. we really couldn't go more than 5 kph maximum and had to use a spotter several times to avoid going over the edge. when we encountered a car coming the other direction we all got out and tried to figure out how one of us was going to drive backwards until there was a turnout.
it took us 2 hours to to go about 5km.
Not a road though a field, it wanted me to use a muddy ploughed footpath in the actual field itself.
Wild back road through a field? Yes please, every time.
Recently though it decided to take me on an extremely annoying new route that has me going through a bunch of tiny seemingly abandoned towns with lots of backroads and even unpaved roads all to save less than 5 minutes.
Now I have to make absolute sure I select the proper route beforehand. But even when I do that it constantly nags me along the way that it has determined there is a faster route so I need to dismiss it. I can't trust it to not take me on some wild back road through a field.