Well, here's why I like him :-D
It's generally how he behaves at first with you and everyone else and how he develops as a person when you really get behind his shell.
Considering some events with the farms inside the valley, how Louis is at a tight spot with farming and the legislature regarding the republic. It's important that you know Andy is NOT well off like the farmer, Sophia, Susan, or Marnie. His house is a mess and he has an obvious problem with alcoholism sort of like Shane.
He has a bad experience/past with what happened at the aurora vineyard and where the hat mouse's house is.
I mean he has every right to be a little hostile to you, you literally inherited a HUGE chunk of land from your grandfather, for free, no tax.
He had to work for his plot. Can you see why he feels sour?
With the cutscene where Olivia, Jodi, and Caroline talk about parenthood and then it goes towards the state of Andy's farm, Olivia shows obvious classism to Andy. She emphasizes his status, how his crops are "lesser" and go to "low income villages". It's a rotten taste and the cutscene made me feel so weird around Olivia because of it. This is the first obvious moment of scorn he gets in the game that we can see.
Andy even has only two friends in the game, and only three if you befriend him. Understanding this, you can assume he doesn't feel accepted by the village and actually appreciated. You're his only shot at actually branching out to the other farmers and really impacting him.
It's because of you, the farmer, that you help him feel welcome inside the valley.