Focus narrows in the winter, doesn't it? Small things take on greater importance. A hot cup of tea, a warm bath at the end of the day, are as great a source of pleasure as summer's picnic basket brimming with the bounty of the season. A fire in the fireplace is more than good enough. Save the s'mores for July.
I think it's because summer demands grand gestures. Color! Excitement! But winter pulls us back in to ourselves, back down to a simpler scale. Summer wants a Whole! Entire! Vegetable! Garden! Winter is happy with a potted rosemary plant on the windowsill. Summer wants landscaping projects and parties on the patio! Winter? All winter wants is a well-shoveled path.