Since Israel's inception, the Mossad has been one of the most effective and fearsome intelligence agencies in the world. More comparable in its capabilities, expertise, dirty tricks operations and success rate to the KGB than any Western espionage group, the word "Mossad" was feared in Arab nations until about 1997, when a colossal blunder forced Israel to make a public relations move and release 70 Hamas terrorists, including Sheikh Yassin (who the Israelis later killed in a targeted assassination).
Mossad's real-time intelligence failures, at the least, harmed Israel's recent efforts in Lebanon. But The Monk agrees with General McInerney (click title for article) that Israel politically failed to execute its plans against Hizb'Allah. But the Mossad's failures only hurt.