Why there is restriction in fluorine to an octet?

Flourins has 2s2 and 2p5 configuration and total 9 electrons in outermost shell. There are two possibilities for fluorine i.e. either to complete the outermost shell or to follow the octet rule. If it follow the octet rule there will remain 4 electrons in 2p. Hence its reactivity towards metals or other compounds will differ which is against its nature.Thats why flourine shows restrictions towards octet rule