How does informal organisation support the formal organisation?

Informal organisation supports formal organisation in many ways, some of them are as follows:
(i) Quick feedback Prescribed lines of communication are not followed. Thus, the informal organisation leads to faster spread of information as well as quick feedback.
(ii) Social needs It helps to fulfil social needs of the members. This enhances their job satisfaction, since it gives them a sense of belongingness in the organisation.
(iii) Flexibility In formal organisation, rules and policies are fixed, thus it is rigid in nature. On the otherhand, in informal organisation, no such rules are there, thus leads to flexibility.