People
Don’t smoke too much, drink too much, eat too much or work too much. We’re all on the road to the grave–but there’s no need to be in the passing lane.
— Robert Orben

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
A joke about moderation: the speaker lists things to avoid overdoing, then admits everyone is heading toward the same end anyway. The punchline says there's no reason to hurry, using the passing lane on a road as a picture of rushing toward that finish.
Context reviewed