A standard single-tip cane makes contact with the ground at one point — a rubber tip roughly the size of a quarter.
Every time you lean on it, your full body weight passes through that single point. If the ground is slightly uneven, the tip shifts. If your footing is slightly off, the cane doesn't compensate.
If your weight moves at an angle, which it does with every step, naturally — the cane doesn't follow.
That slight instability is what your body picks up on. It's what creates the need to constantly correct yourself mid-step.
It's what makes walking feel like something you have to think about, instead of something you just do.