Why won't my garage door remote work unless I push the button to turn off the light first?
CFL bulbs used in the opener cause signal blockage until fully lit. I don't know why but while the CFL bulb is flickering the signal gets blocked.  After the bulb warms up, and stops flickering (about 30-60 seconds) your garage door remote should work fine. This can be tested easily enough. Does the remote open your door when you just get home and open door? Door opened because the light was off.  But when you are leaving the garage, you use wall switch to open the door and can't close it by remote while trying to drive away.  That's because the CFL bulb is still warming up after you just opened the door to leave. Easy solution is to change out CFL bulb with incandescent light (old style bulb with filament).  I've heard that LED lights do this too, but my hunch is that some folks think CFLs are LEDs and are calling them by the wrong name. LEDs are instantly on and quite expensive, while CFLs flicker until warmed up and purchase price is pretty low.
So change to incandescent in Door Opener and happy motoring. Appliance bulbs are perfect for Garage door Openers.