Why is Willy so bent on being well-liked?

It's clear that Willy Loman is not a bad person. He cares about his family, and he wants his kids to be successful.

And yet, on first glance, Willy Loman, the main protagonist, could come off as someone who is incredibly unlikable. One of the main reasons for this is that he is constantly pushing his ideas for success on his two sons even though those very ideas are probably the reason why his family hasn't struck it rich yet. He seems deluded. He literally has hallucinations about past events, and he can't distinguish past from present. He seems to be a man that is stuck in the past, unable to come to terms with the truth in the future.

And all of that is true. However, as is the case with all good stories, there's more to it underneath the surface. Willy's father left him early, and whether he intended to abandon Willy or not, Willy never received the fatherly love that he needed as a young child. Good thing he had an older brother, right? Except that his older brother also ends up leaving. Willy never received enough love from his family growing up, and as a result he ends up looking to others to try and compensate for the affection that he didn't get at home. This is why he develops a perspective based around being well-liked. He associates being well-liked with everything in life. He can't come to grips with the idea that he is wrong about this part, which is one reason he is unwilling to take a job from Charley even when he is laid off. To him, Charley is way less "well-liked" than him, so the idea that Charley is more successful than him is unfathomable and humiliating. Even when faced with overwhelming evidence that what he is doing isn't working, his need to be well-liked still takes priority, thus putting him in an endless cycle of failure.

His need to be well-liked goes beyond his actions in business. When he deals with Biff, he doesn't bother to correct Biff's flaws. He doesn't make Biff study for a class that Biff ended up flunking. He doesn't try to correct Biff's habit of stealing; he even encourages it to some degree. He doesn't want to risk losing Biff's affection for him, and thus he allows Biff to feel as though he is the perfect human being. As a result, Biff is unable to find success in later life because his flaws have been allowed to grow to the point where they were essentially permanent. And yet, Willy is unable to see the flaws in how he views the world because he is still blinded by his need to be "well-liked." As he sees it, as long as someone is "well-liked," they will be successful, even if that person has nothing else to offer.

In summary, Willy's biggest flaw seems to come from what he lacked in his childhood. He has spent his entire life trying to fill a hole that should have been filled in childhood by the people he needed most. Instead, the lack of love he received from both his father and Ben results in a distorted worldview that Willy is never able to escape from, even when it seems obvious that he is wrong.