Here's a Tale....

about two frogs (credits to my dad for sending this to me in an email).

This isn't the only version of this story I've heard actually, if you cruise the net you can find many
alternate stories each with a similar message, however this is one of the better ones I've heard:

Two Frogs
By: Author Unknown

A number of frogs were traveling through the woods. Two of 
them fell into a deep pit. All the other frogs gathered 
around the pit. When they saw how deep the pit was, they 
told the two frogs that they were as good as dead.

The two frogs ignored the comments and tried to jump up out 
of the pit with all of their might. The other frogs kept 
telling them to stop, that they were as good as dead.

Finally, one of the frogs took heed to what the other frogs 
were saying and gave up. He fell down and died.

The other frog continued to jump as hard as he could. 
Once again, the crowd of frogs yelled at him to stop the 
pain and just die. He jumped even harder and finally made 
it out.

When he got out, the other frogs said, "Did you not hear 
us?" The frog explained to them that he was deaf. He 
thought they were encouraging him the entire time.

This story teaches two lessons:
1. There is the power of life and death in the tongue. An 
   encouraging word to someone who is down can lift them up 
   and help them make it through the day.

2. A destructive word to someone who is down can be the 
   push over the edge. Be careful of what you say. Speak 
   life to those who cross your path. Anyone can speak 
   words that can rob another of the spirit to push forward 
   in difficult times. 

It's a pretty interesting story gives a little bit more drama to Thumpers advice, it also reminds me vaguely
this and the alternate versions of a "dangerous (or hazardous) attitude" a term they use in aviation (there are 5 dangerous attitudes), the one I'm thinking of is Resignation, the "I can't do this, I give up (because I have no control)", the other frog clearly had it (with no help from his fellows!).