Explaining the joke's punchline makes it unfunny (which is funny).
- Cross the river to visit the unabridged version HERE. Get it? Because bridges are used for crossing rivers! Now the joke is ruined.
http://tvtropes.org/pmwiki/pmwiki.php/Laconic/DontExplainTheJoke
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Explaining the joke's punchline makes it unfunny (which is funny).