Origin
The line, fools rush in where angels fear to tread, was first written by Alexander Pope in his poem An Essay on Criticism (1709).
Explanation
Foolish people usually do not understand when a situation is dangerous, so they are not afraid to do things that would frighten more sensible people. Ignorant or inexperienced individuals get involved in situations that wiser persons would avoid. The rash or inexperienced will attempt things that wiser people are more cautious of. A person who does not plan ahead and think about matters mindlessly becomes involved in risky or unfavourable situations which prudent people avoid. People without good sense or judgement will have no hesitation in tackling a situation that even the wisest would avoid. It means that foolish or ignorant people tend to do dangerous things that more sensible people stay away from because the fools do not usually understand the gravity of the danger they are getting themselves involved with.
Examples
Alan : Bob is too scared to confront the boss, so I’m going to meet the boss.
Jane : Fools rush in where angels fear to tread.
I know that fools rush in where angels fear to tread, so I will not get mixed up in the UK debate on the euro.