In addition to what the other educators have shared, I'll argue that Anse's complete helplessness and uselessness as a person make him need other people—and for those people, such as his neighbor, Tull, to feel needed by someone is an extremely powerful emotion.
Let's clarify Anse's neediness by finding some examples of him being completely helpless on his own.
First, here he is, finding it a great annoyance that he has to put on his own shoes:
He puts his shoes on, stomping into them, like he does everything, like he is hoping all the time he really cant do it and can quit trying to.
And here he is, looking like he can't dress himself properly:
Anse's wrists dangle out of his sleeves: I never see him with a shirt on that looked like it was his in all my life. They all looked like Jewel might have give him his old ones.
Next, here's Anse being completely oblivious to his own helplessness, repeating his mantra as he claims, again, that he doesn't want to owe anyone for their help, even though he's constantly accepting it:
I wouldn't be beholden, God knows.
And what do others make of Anse's total helplessness, his complete dependence on others? Sure, they're annoyed, but at the same time, they can't resist it. They have to help. They're drawn to his neediness.
Here's Armstid, commenting on the ineffable quality of Anse's that inspires others to help him, even when they don't want to, even when they know they'll regret it:
Because be durn if there aint something about a durn fellow like Anse that seems to make a man have to help him, even when he knows hell be wanting to kick himself next minute.
I'd argue that what Armstid is touching on here is, again, Anse's neediness.
When others need us, we feel valued, important, empowered, and deeply connected to the person in need. According to the 2007 study cited below, feeling needed by and useful to others is not just a powerful and positive emotion for us but may also be associated with living longer lives.
In other words, feeling needed is essential to our humanity and to our existence.
I suggest that this feeling is what inevitably draws characters like Tull and Armstid toward helpless people like Anse.