The big thorn, the obstacle that is difficult to solve; However, a small thorn can be described as a giant to be rid of.

When eating fish, small thorns are more troublesome than big thorns. Because big thorns are easy to find, small thorns must be removed with great efforts.

Being a man, minor faults are more difficult to correct than major faults. Because major faults are easily found, minor faults must be found with extra care.