As a secular guy and an atheist, celebrating the festivels is fair on my part?

oh my fellow beings out here! i m very much secular-no religious activities will bother me even a drop in my life. moreover i dont believe in God or supernatural things. i dont believe in any religion even i was born hindu. i believe in humans and their character. but i love to celebrate festivels very much whether it is going to be diwali, christmas, ramzan or any other. the only reason why do i celebrate festivels which is a byproduct of religions is bcoz it brings more happiness and brings our friends @ family close together atleast once in a year of our busy schedule. for me festivel is a day of happiness. i dont think we have to be adhesive to any particular religion's festivel. every festivel brings happiness eventhough it adheres to a specific religions' views. let the festivels be meant for praising Gods. but i think, for human beings, it's happiness.