So you have done your preparation - improved your horse's diet for at least several weeks before shoe removal, read all the books and you are ready for the big day.
Excitement is mixed with a bit of trepidation; but you know it will be ok because all the horses you hear about have been just fine.
Only it's not.
Your horse was ok immediately post shoe removal but within hours they are looking uncomfortable, maybe just on one leg, maybe two, or horrors all four.
Well - you need on the spot experienced barefoot help to identify the actual problem but here are some starters for ten.
1 - the shoe remover decided to trim the feet and did a shoddy job of it
2 - your horse has previously undiagnosed laminitis or LGL issues
3 - the increase in blood supply once the shoes are removed can cause 'pins and needles' type effects
4 - muscles which had adapted to how the horse held its body when shod, are in the process of change
5 - when turned out post shoe removal your horse ran off bucking and strained something (oh yes it happens)
6 - your horse has thin soles (which can be improved) and is feeling the ground for the first time in ages (shoes numb the feet)
7 - your horse has thrush and can feel it now the shoes are off
8 - your horse has a poorly developed digital cushion/heel area and can now feel it
9 - your horse had wedge pads or egg bars or natural balance shoes on previously and these have upset the internal structures of the foot/foot balance and/or put strain on the tendons
10 - your horse has something else, entirely unrelated and it is just coincidence (for example pain in the cecum)
And don't forget, if in doubt always call your vet. A horse should not be left miserable and in pain. And - try to have boots to hand in case you need them. Otherwise organise things so you can continue to work your horse while in transition without having to overly test them on horrible surfaces.