...the Jewish people are forced to withstand the fluctuation between two contradictory modes of life: love of G-d at the time of prayer, and then total immersion into the physical world during one's business and private affairs the rest of the day. Chassidic teachings compare this situation to a dream, because in a dream two opposite, contradictory phenomena can co-exist simultaneously... (Collected Talks of the Lubavitcher Rebbe, #15, 346)
When the Lord will return the exiles of Tzion, we will have been like dreamers... (Tehillim, Psalms - 126)
Contradiction: A physical world, no apparent room for anything not most mundanely physical, yet it's purely a generation of a spiritual world and intimately bound to it, yet that seems unreal. When the facade is pulled away, we will know what was the dream and what is real.
But today, we are dreamers.
BS"D - בסיעתא דשמיא