The door stops partway up for no reason, or opens fine and then refuses the next time. Some days the keypad works and some days it does not.
Press the button and the opener hums for a second, then quits. The trolley is jammed hard against a bolt at the very end of the rail near the motor and will not budge in either direction.
The door used to glide up with a soft hum. Now there is a sharp clack every second or so, and if you stand underneath you can see the belt sagging below the rail and slapping it on the way up.
During the ice storm the power was off for two days. You came home in the dark, found the door dead, and had to climb out of the car to pull the red cord in the cold.
Since shelving went up along the garage wall, the door will not close and both sensor lights are dead. A screw or staple may have gone through the thin wire that runs from the opener to the sensors.
The remote opens the door only when you are almost underneath it. From the end of the driveway you press five or six times and nothing happens.
Your daughter gets home from school an hour before anyone else. She has lost two house keys this year, and the garage keypad code has been shared with half her class.
Your garage is detached and has no side door. The remote is dead, the keypad is dead, and the small round lock in the top panel is meant to be your way in.