Why did Lavan (who was in no way on a par with his sister and daughter) run to greet Yakov?
Rashi: Lavan ran when he heard who had arrived. He figured that if the family's servant had arrived with ten camels laden with 'goodies', imagine what the master must have brought with him! So he ran out to see what was in it for him. 1
Seforno: He ran when he heard how Yakov had removed the stone from the well single-handed.
Targum Yonasan: He ran because he was intrigued by his nephew's strength and piety, and by all that happened to him - the episode of the B'rachos, the revelation in Beis-El, how he had rolled the stone off the well and how the well began to flow and rose to meet him.
Tosfos ha'Shalem (6): Lavan wanted to steal from him.
It is truly remarkable; almost a hundred years had passed, but Lavan's greed had not abated one iota! (EC).
Yakov kissed (Menasheh and Efrayim) and then embraced them (Bereishis 48:10). Why did Lavan embrace and then kiss?
Rashi (from Bereishis Rabah 70:13): When he saw no camels, he thought that perhaps he had brought gold coins with him, which were hidden somewhere on his body, so he embraced him; when he found nothing, he figured that he must have hidden some jewels in his mouth, 1 so he kissed him.
Ha'Emek Davar: One who comes from afar, first he stretches out his hand to embrace, and afterwards he kisses. Below, Yakov was already close to Efrayim and Menasheh.
Ohr Yechezkel (Darchei ha'Avodah p.184): Does one hide jewels in his mouth? This is lunacy! This shows that bad Midos (e.g. lust for money) can bring to lunacy.
What exactly did Yakov tell Lavan?
Rashi: He told him that he was running away from his brother and related what had happened on the way - to explain why he came empty-handed. 1
Rashbam: That his parents had sent him, to be with his family.
Ha'Emek Davar: He informed him that he came to escape his brother, according to his mother's instructions. Seforno - he also said that he did not come for income.
Bechor Shor: He told him about getting the Brachos and Bechorah, so Lavan will want to give his daughter to him.
Ohr ha'Chayim: He told him about his Chachmah to get the Bechorah and Brachos, so Lavan will know that he is crafty to get what he needs, and he told him about the rock, so he will not know that he is very strong, and about watering the flock, to teach that Yakov endears him and will act straight with him.
Why does it say "Ben Achoso"?
Ohr ha'Chayim: Rachel did not tell Lavan that Yakov said that he is his brother [in deceit], only that he is Ben Rivkah
Why did Lavan bring him into his house?
Ohr ha'Chayim: He thought that perhaps Yakov's property will come later. He entered him until his property will come.
Why does it say "va'Yaged Yakov l'Rachel", and "va'Ysaper l'Lavan"?
Malbim: Hagadah is telling what is relevant to the listener, and he needs to know it. Sipur is telling what is not relevant to the listener. Lavan had no love of relatives in his heart.
Why does it say "Sheima Yakov"?
Ha'Emek Davar: Rachel was not aroused through hearing his name, only that he was Ben Rivkah. Lavan was aroused; he had already heard about Yakov. Whoever learns Torah covertly, the Torah announces about him externally (Mo'ed Katan 16b).
Why does it say here "va'Ychabek Lo va'Ynashek Lo", and regarding Esav it says (33:4) "va'Ychabekhu va'Yishakehu?
Ha'Emek Davar (here and 33:4): Va'Ychabek Lo va'Ynashek Lo" implies that they hugged and kissed each other. Yakov did not hug and kiss Esav, whom he called 'my master.'