Too Much of a Good Thing

When I put single peanuts on the top fence rail outside my window the squirrels snatch them up immediately.  When I put a whole pile on the fence they become skittish.  They run up then back away then run up and sniff and back away then they proceed to snatch one.  Are all animals afraid of too much of a good thing.  Is this why humans are afraid of bliss?  It is simply too good to be true that we have access to this state of mind at most times.