People hate resistors for their LEDs

Pin 13 led has a resistor. I hope you're joking about not getting it to blink.

Feed a led low enough V and you don't need a resistor but at 5V the lifetime is amazingly short.
Back in the 90's I saw a 555 circuit that ran red leds on very short 9V pulses yet allowed a lifetime of minutes.... it said.... I never tried. The purpose of that one was to make very bright pulses for a fake laser.