For a "classic" which comes so widely recommended, I found it so-so. Yes, it has disturbing scenes, but I didn't think it was frightening or put me off camping/trekking. It just high-lighted you need to be armed and ready to use your arms if necessary.
Not for the faint hearted, Deliverance made it to the list of Top 100 Most Disturbing movies of our times. Nature can be very very unforgiving and this movie just shows you that. After watching this movie, you will think twice before going out for a jungle trek. #MustWatch