system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does a car in 1st gear stall when the clutch is released too fast/early?
gpt
To reduce it to its simplest terms, there is an explosion in the cylinder that pushes a piston down which, through various gears, pushes the car forwards. If the resistance to the car  moving is greater than the force on the piston it doesn't move and all the processes that depend on the engine turning over to get ready for the next explosion don't happen.

Too little accelerator before you release the clutch puts less fuel in so less force. Too fast and enough little explosions that add up to overcome the car's mass to get it moving haven't had time to happen.