According to Osho, when you feel ecstatic but others aren't celebrating, don't oppose them—be with them. Celebrate their sadness: outwardly share their mood (even cry), while inwardly rejoicing in the beauty of the moment. Flow with whatever is, never against it; this empathic 'being-with' dissolves ego, harmonizes relationships, and is the religious way to live—like Diogenes, who always flowed with the whole.
Join their mood on the outside, but keep your inner joy and love flowing inside.