I take size 11 (or 46) shoes, and have done for many years. Look in my cupboard and see size 11 (or 46) trainers, work shoes, "smart" shoes, climbing boots, walking boots, cycling shoes.
Today I went to Evans Gatwick to have my soul drained out of me. Select shoe, Shimano MT34) from Magic Computer. Scrawl number on piece of paper. Hand paper to young lad behind counter. Wait. Wait a bit more. Shoes arrive. try them on. They don't fit. My previous Shimano shoes, MT33, were size 11 (or 46) and fitted beautifully. Even Shimano's shoe sizing guide says they should fit. Ask for size 47. None in stock, would I like 48s? Yes please. Wait, wait, wait some more. After 10 minutes I give up and go.
Why does it have to be so tricky? There's reviews that say "get a size larger than usual". Why? Why can't manufacturers just make them to the size it says on the box? It's not even as hard as the whole L, XL, XXL clothing size nonsense either.