This line from Simon and Garfunkel's The 59th Street Bridge Song (Feeling Groovy), is, I think, the most perfect evocation of a certain kind of mood I've ever come across.
Imagine a warm summer afternoon -- sunny, but not too hot. You're beside a river, or a lake, and the light glints and flashes and sparkles off the top of the ripples. There are trees, and they filter the sunlight so it makes shifting patterns on the ground, as an almost imperceptible breeze moves the leaves. The scents around you are natural and fresh, pine or citrus, flowers or herbs.
You have just eaten a simple, but delicious, picnic lunch, and possibly drunk some wine, if that's your thing. You are with a group of friends -- people who make you laugh, who you can talk to at a more than superficial level, who stimulate your mind and wit. At this moment, you love them all, even if they irritate you from time to time.
Amongst this group is someone really special to you -- the dearest of your friends, a lover, husband, wife or a child.
The conversation has drifted almost to silence, just broken by the occasional comment, but there is no awkwardness - just content and relaxation and the knowledge that you are where you want to be, and that the people around you are the ones you want to spend this time with.
You lean against someone, or they lean against you, and your eyes close, softly.
Drifty, dreamy, perfect.
That's "dappled and drowsy and ready to sleep".