You are more apt to see these types of cracks on a garage floor that has a hard smooth troweled surface than one that has a broom finish.
Garage door exterior surface cracked.
Wooden door patch repair an old wooden garage door made of fiber board wood or other composite wood materials can become warp and receive water damage from years of rain and snow splashing and pelting its surface.
Caulk paint cracking or crawling the cracking of the paint film over a caulked area.
If your garage door is metal or vinyl it is much more difficult and even impossible to fix.
Gravel and or sand on top of the sub grade.
Repairing the doors requires a little work and depending on how large the crack is could be.
Cracking due to poor compaction of sub grade before pouring a concrete slab it is important to prepare what is often called the subgrade which usually involves compacting the sub grade and base i e.
Actually fixing a crack in a garage door panel can be a difficult and even impossible task.
If the garage door panels are wood then yes a garage door panel that is cracked could be fixed using wood fillers and glue.