The past & the future.

"The past came back to her in one of those rushing waves of emotion by which people of sensibility are visited at odd hours."
Henry James

Every now and then some memories of simple, perfect happy moments from my past come back to me, apparently without any connection to what I'm doing at that present time. A flavor, a smell, a sight. A fully content heart. While these are great memories, they worry me and make me melancholy.

Are they coming back because the future is failing to excite me?