It is an offence to consider Lord Shiva or Lord Brahma to be equal to or independent of the Supreme Lord. But it is also an offence to disrespect the devotees of the Lord. As such, it will certainly be an offence if one fails to offer due respect to Lord Shiva.
Lord Shiva is a very special personality, and one must make sure to understand Shiva tattva properly to ensure that one is saved from committing any offences. Some people take Lord Shiva to be the Supreme Lord, equal to Lord Vishnu, but that is certainly not correct as he is not untouched by the modes of nature. Being the predominating deity of the mode of ignorance and responsible for the destruction of the material universes, he is in contact with Maya and thus not situated in pure goodness as Lord Vishnu. However, to consider him to be an ordinary jiva, bound by the modes of nature, would account to a grave offence as well, as he is the master and husband of Durga devi, the external energy of the Lord. This raises the question as to who exactly is Lord Shiva then. He is not the Supreme Lord, but he is also not a jiva, then who is Lord Shiva? What is this special tattva known as Shiva tattva? The answer to this most intriguing question is given by Lord Brahma in his Brahma Samhita,
kṣīraḿ yathā dadhi vikāra-viśeṣa-yogāt
sañjāyate na hi tataḥ pṛthag asti hetoḥ
yaḥ śambhutām api tathā samupaiti kāryād
govindam ādi-puruṣaḿ tam ahaḿ bhajāmi
Just as milk is transformed into curd by the action of acids, but yet the effect curd is neither same as, nor different from, its cause, viz., milk, so I adore the primeval Lord Govinda of whom the state of Sambhu is a transformation for the performance of the work of destruction.
Just as Yoghurt is a transformation of milk and can therefore not be considered as anything but milk, but can also no longer function as milk, for making ghee or other milk sweets, due to being transformed, similarly Lord Shiva is certainly not an ordinary jiva but is also not the Supreme Personality of Godhead. It has also been mentioned in the shastras that a perfected living entity can develop upto 50 transcendental qualities and the Lord is the only one who has 64 qualities, but Lord Shiva is the only one who actually possesses 55 qualities. Such is the inconceivable position of Lord Shiva. It then becomes necessary to understand how one should show due respect to such a great personality. And for this our acharyas have said, Vaishnavanam Yatha Sambho, Lord Shiva is the best amongst the vaishnavas and should therefore be offered great respect accordingly. Lord Shiva himself is always engaged in meditating upon his most worshipful Lord and glorifying his names, forms, qualities and pastimes. There are numerous pastimes where Lord Shiva has the most wonderful exchanges with Lord Ram and Lord Krishna. It is Lord Shiva who composed the famous Radha Kripa kataksha stotra as well. Lord Shiva is also kshetrapal, or the personality protecting the dham and no person can enter the abode of the Lord without first receiving the permission and blessings of Lord Shiva. In Sridham Vrindavan, Lord Shiva is present as Gopeshwar Mahadev, as he once took on the form of a Gopi with the help of Vrinda devi and tried to enter the Rasa dance. Seeing this new Gopi in their midst, all the Gopis came and enquired from her about her name, her village and her family. Lord Shiva, however, had not received all these attributes from Vrinda devi and was therefore unable to give them an answer. Seeing that this Gopi was not one of them and was not even introducing herself properly, they concluded that she was not fit to participate in the Rasa dance and wanted her to leave. At that time Sri Krishna revealed the true identity of the Gopi as Lord Shiva and requested the Gopis to be merciful upon him. Since then Lord Shiva has been guarding the Rasa mandal, allowing only qualified devotees to enter into the most confidential pastimes of the Lord.
Sri Shivaratri is fast approaching and therefore we should all try to understand the exalted position of Lord Shiva as the best of the Vaishnavas, so that we may be able to give him due respect and veneration as an exalted vaishnava. Let us therefore pray to Lord Shiva to bless us with shuddha Krishna prem so that some day we may be able to serve Sri Sri Radha Shyamsundar in their pastimes in Vraja.