And He said to them: With desire I have desired to eat this pasch with you, before I suffer.
Et ait illis: Desiderio desideravo hoc pascha manducare vobiscum, antequam patiar.
Luke 22: 15

Jesus Christ is God Almighty.  He transcends time.  Time is His invention.  He exists outside of it. That is why He said, “Before Abraham was, I AM.” Therefore, when He says something like, “I’ve really been looking forward to this…” it means that He is being just about as emphatic about something as possible.  He is emphasizing that “this” is an event of infinite importance.

Given that, are we really to believe that Jesus Christ was referring to a symbolic light snack as this event that He had “desired with desire” to institute?

No.  He was referring to the institution of the Holy and August Sacrifice of the Mass, and in particular to the Sacramant of the Altar, the Eucharist, the transubstantiation of mere unleavened bread and mere wine into literally, not figuratively nor symbolically, but really and truly the physical, substantial presence of His Body, Blood, Soul and Divinity.

Why? Because love. Love, love, love. Infinite, condescending, total, complete love.

The Mass and the Eucharist are the most important thing in the universe. They are the pounding heart of not just the universe, but of existence and reality.

“Our own belief is that the renovation of the world will be brought about only by the Holy Eucharist.”

– Pope Leo XIII