When you are doing something involving interacting (e.g placing blocks or hitting a mob/player), some players keep moving forward. Also, if you jump while running, you will keep jumping. This is a major problem for a few reasons, some of the more major ones being:

1. You are running down a cave, and you let go of your move forward key. Without realizing, you keep running, and it's too late for you to stop yourself! You run straight into a lava lake and lose all of your ores and materials.

2. You are PvPing (fighting another player) and are running toward them. You try to hit them, but you run right by them, giving them the chance to hit you while you can't hit them.

I've researched this topic, and what I've learned is this:
Minecraft uses something for java called lwjgl. Minecraft's version is outdated, and this is apparently what is causing the problem. I tried manually updating lwjgl, only to get a flashing screen. No more ideas except for telling Mojang