אברהם vs. יצחק

We often think of Yitzchak as being exactly like Avraham. They went through very many similar experiences: they both had to leave, the identity of their wives were questioned, the Plishtim were jealous of both of them, they both eventually had a son after thinking their wives were barren, they both had a righteous and wicked son, and they both lived in times of famine. However, despite alll of these similarities, they both respond to these situations in very different ways. This difference in response shows that Yitzchak came and repaired and completed Avraham's actions, which is why he got certain things that Avraham himself never got.

We read an article by Rav Amnon Bazak that explained in detail some of these differences:

Barrenness: although they were both faced with the challenge of their wives being barren, they react differently. Avraham doesn't pray for a child, and when he states that Hashem hasn't given him a son, we don't see a mention of Sarah. However, it is very clear that Yitzchak prayed and included Rivkah in his prayer.

Famine: They both endure a time of famine. However, unlike Avraham, who decided to leave Eretz Yisrael, Yitzchak stays within the boundaries. The meforshim have various opinions on Avraham leaving the land - some see it as a transgression which caused the Galut to Mitzrayim, and some think it's him passing a test. However, it is agreed that Yitzchak remaining in the land is definitely praiseworthy. Because of this, Yitzchak receives a command that was never given to Avraham: to remain always in the land. Since Yitzchak was so devoted to the land, he gets an eternal connection to the land and the promise that Hashem will "always be with him."

I think that it's interesting that once you look deeper and deeper in to their personalities and reactions, you see how very different they are from one another, which is something you don't see at first glance. It's yet another one of those things that show us that we must look underneath the surface for a real explanation.