It’s a safe bet that Ya’akov Avinu could not wait to get out of Lavan’s house. So why after Lavan agreed to let him go, and further, even paid tribute to Ya’akov, saying, “Nichashti, va’yevarcheini Hashem biglalecha,” (30:27) acknowledging that Hashem blessed his home because of Ya’akov, did Ya’akov insist that he will stay on and work until he had his own flocks and only then leave? Why not cut and run – why wait that extra six years accumulating sheep?
If you’re the Rogatchover, the answer (link) is that Ya’akov wanted to fulfill his neder of giving ma’aser, i.e. ma’aser beheima. Since sheep that has been acquired is exempt from ma’aser beheima, Ya’akov had to accumulate his own flocks. This is also why he kept his sheep separate from Lavan’s, so as to avoid a ta’aroves of those which were chayav in ma’aser with those which were not.
I wanted to share a less technical answer but an equally beautiful one that is offered by the Ostrovtzer in his Me’ir Einei Chachamim (vol 3). I mentioned last week the teaching of the Ch. HaR”IM that even if a Jew is far from where he should be, so long as he recognizes and is moved by the appearance of a tzadik, there is yet hope for his return. The Ostrovtzer’s answer reflects the same idea. He explains that Ya’akov thought that his mission in the galus of Lavan’s home was finished with the birth of Yosef and it was time to return and confront Eisav. However, when he came to take his departure and he heard Lavan acknowledge the fact that bracha came to his home only through Ya’akov, he realized that there was yet some goodness left in Lavan’s heart. So long as Lavan recognized that everything good came though the tzidkus of Ya’akov, not his own corrupt persona, there was something to stay behind for.
Only after those years tending the flocks passed and Ya’akov overheard Lavan’s sons saying, “M’asher l’avinu asah es kol hakavod hazeh,” (31:1) that Lavan was the source of his own wealth and prosperity which Ya’akov drained and made his own, did Ya’akov decide that it was then truly time to depart.