"I think of my time with Amy as a stick of Fruit Stripe gum. Sweet and enjoyable at first, but ultimately a flavorless lump of sadness."
Why it's apropos: Let's contextualize this quote a bit. When Sheldon compared his love life with a wad of flavorless gum, he was in the midst of excruciating heartbreak and, at the time, everything seemed dreary and unappetizing.
In a way, this comparison isn't too far off for life and relationships, in general, because there will always be exciting adventures followed by mundane, day-to-day tasks; but, it's the wonderful moments and memories that make all the "lumps" in the road completely worth it.
Savor the sweetness, Sheldon!
"The Mystery Date Observation" (Episode 8, Season 9)