Unchecked math.

[fps]

How deadly is an unchecked math? Since every math in the assembly{} block is unchecked, what could go wrong?
See here.

    uint256 a = type(uint256).max;
    uint256 b = type(uint256).max / 2;

    assembly {
        let sum := add(a, b)
    }

    // What could go wrong 👀?