The real message of “Friday Night Lights” is a message about the joy of little things: the awkward thrills of a first kiss; the strange blessing of an unexpected rainstorm on a lonely walk home from a rough football practice; the startling surge of nostalgia incited by the illumination of football-stadium lights just as the autumn sun is setting; the rush of gratitude, in an otherwise mundane moment, that comes from realizing that this (admittedly flawed) human being that you’re squabbling with intends to have your back for the rest of your life. “Friday Night Lights” embraces the rough edges, the fumbling, the understated beauty and uncertainty of the everyday. It’s rare for a TV show to acknowledge that happiness is a fragile, transient thing. Although the tenure of “Friday Night Lights” may have proved just as fleeting, its exquisite snapshots of ordinary life won’t fade from our memories so quickly.