That would be fine if the LED was a resistor, but it is a diode. At the push voltage, it doesn't offer any electrical resistance, this is provided by the ballast resistor or a constant current source of which one is needed for each series chain of LEDs (including chains of one).
Don't be misled by LED flashlights - they usually rely on the internal resistance of their battery. To increase confusion, some LEDs have the required current limiting built into the package.
As a general rule, as with many things in life, the brighter it shines, the shorter its life.