It's not a "my bike in front of" but I do have a candidate for the worst road closure obstruction that I saw on my Christmas Eve ride - a whole 1.3 miles of road was closed (I measured it on Strava afterwards) for something that blocked less than one lane for maybe 2-3 yards worth of bollards and cones.
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Possibly would have been more sensible to have automated temporary traffic lights to let one lane through at a time, but Thames Water applied for a full road closure for over a week with multiple signs leading up to it in both directions telling people it was totally shut. Luckily I ran into a local resident coming the other way and he saw I was looking at my phone to find a diversion (there wasn't one signed) and said that I could ignore it and carry on through. At first I thought maybe it was one of those ones where cyclists and walkers could get by (maybe I'd have to dismount) but when I came to it I had to laugh as there was still one and a bit lanes available.
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The closure was the whole stretch of red above, with the actual bollards being where the circular marker is (I took the photo looking backwards once I'd gone past it).