Seriously? Have you been hit on the head recently? Are you suffering from short term memory loss?
Martin Jol got back to back top 5 finishes, the first time we'd done that in over 20 years. A rocky start to the next season though and he was promptly sacked - half way through a game no less.
Juande Ramos won our first (and until Ange our last) trophy in 10 years, but 2 points from 8 games at the start of next season - sacked.
Harry Redknapp, got us to a cup final, and finished 5th once and 4th twice during his tenure, including qualifying for the Chapions League for the first time. Didn't stop Levy sacking him.
Pochettino, got us to two cup finals including Tottenham's first ever Champions League final. He also finished in the top 5 for 5 consecutive seasons (including a couple of quixotic tilts at the title). The only other Spurs manager to achieve that being Bill Nich. Yet the first sign of a blip he was out on his ear.
Mourinho - Sacked on the eve of a cup final, he'd likely have won.
Conte - top 4 in his first season, and 4th in his second when Levy sacked him.
And then there's Ange...
It doesn't matter how successful our managers are, sooner or later Levy sacks them.
It's who we are mate.