When you come close to something but don't quite get there.
Just short of success
This phrase originated in the 1920's. Fair grounds would give cigars away as prizes. Prizes were more aimed at the adults then vs. children like they are now. The fair workers would shout out "close but no cigar".... The first written documentation of this word appeared in the 1930's and then became a common phrase.
You finish second in a race
A friend asks how you did
You tell them "I finished in second place, close but no cigar"
Being overconfident and reckless. Not knowing your limits. The phrase comes from the tale of Icarus, a young man who flew too close to the sun and fell from the sky when his wings melted. It's a tale of caution, warning us to remember our limitations.
Person #1: That man was killed by the gang leader, thinking he can take him on.
Person #2: I guess he flew too close to the sun.
Possibly one of the most funniest comedians in the world, has played part in all the great classics, Monty Python films and flying circus, fawlty towers and others, one of the reasons why Britain is Great Britain :D