Something that honestly bothers me is the fandom's perception of Liam before he was turned into a vampire. And this isn't helped by the lack of scenes we get with Angel's human life, that are usually aren't depicting him as a lazy drunkard who chases after women. I feel like, AtS could have explored this more. I wish they had, but I'm not surprised about this because they don't go into Buffy's life pre-Sunnydale for that matter.
But back to Liam I've said before that he was a victim of abuse, both the physical and verbal variations. Given the time Liam grew up in, he was pushed into a lot of expectations as the oldest of two children. You could also argue that Liam could have had other siblings but given the context of the show, it doesn't seem likely. Because if this was the case, Liam's father would have compared him to a deceased older brother in The Prodigal and this never happened.
And given the family had enough wealth for one servant, Liam's family seemed to be well respected. Given the fact that Liam's dad was so obsessed with having a son that would have taken over the family's trade, it speaks volumes to the things that Liam had to endure over the years. For example in The Prodigal, Liam's father says this:
Liam's Dad: It’s a son I wished for – a man – instead God gave me you! A terrible disappointment.
This basically implies that Liam was never the son his father wanted him to be. That Liam wasn't living up to the expectations his father was setting up for him. His family traded in linen and silk, which ironically is interesting given after Liam's change, as both a soulless vampire and ensouled, he wore a lot of silk shirts. Anyway, I'm sure this resulted in Liam being forced to learn a lot about business and trade.
It's not entirely clear on how his family ran this business. They could have had a small shop in Galway's town center that sold the silk and linen to buyers. It's hard telling with the lack of information to come back to. Of course, there could be more in books/comics but I do not own those resources and I refuse to touch the season comics with a ten foot pole.
But given that Liam was a free spirit who wanted to see the world, its unlikely that he would have been interested in this. He wanted to see what world outside of Galway's little bubble. See what's past the coasts of Ireland. His father clearly didn't approve and Liam had most likely started acting out at a certain age. His teens years would be the likely indication and his actions only seemed to get worse the older he got.
However, his father was always the biggest factor. As evidenced by this line from Liam in the same scene before he storms out of the family home:
Liam: Disappointment? A more dutiful son you couldn’t have asked for. My whole life you’ve told me in word, in glance, what it is you required of me, and I’ve lived down to your every expectation, now haven’t I?
This scene always gets me because to me it sounds like when David is acting this out, there's a crack in Liam's voice than you can miss. And maybe I could be imagining it but it adds a layer to Liam even if its subtle.
That he always did what he was told. What his father wanted of him. And no matter what he had done it was never enough to get his father's approval. And this is supported by a previous statement Liam makes:
Liam: As you wish, father. Always, just as you wish.
These two lines signify that Liam was a broken man who still craved the approval of his own father. The possible voice crack I mentioned? Shows to me there's a broken kid under that exterior, who's just as hurt and wounded as the man he turned into.
Back in those times, men always sought out sons to keep the family legacy and traditions going. It was especially common in households that some degree of wealthy like the aristocracy and royalty.
Of course daughters had their own levels of what was required of them (mostly getting married and producing male heirs). And while Liam's family did not live in a large estate home, they were wealthy and respected enough for his father to exhibit this kind of behavior. And it always starts when they're younger, so its easier to mold their children into their parents image.
These next three lines are better explained together:
Liam: No. The madness is that I couldn’t fail enough for you. But we’ll fix that now, won’t we?
Liam's Dad: I fear for you, lad.
Liam: And is that the only thing you can find in your heart for me now, father?
The first part of that certainly plays into the previous points. That Liam was always failing in his father's eyes despite his efforts. The second and last line I could see where some division can happen. I mentioned earlier in this post that Liam was a product of abuse however the middle line could apply that his father did care.
However the way Liam says he wonders if his father only feels fear and disappointment is because his father has no love for him. That makes it thrown into question because given how several scenes before this in the courtyard, Liam's father strikes him and starts berating him. The relationship is messy and there could be underlying signs of abuse.
Just nothing concrete. And Liam cares deeply for his younger sister, as before he walks out the door, he's stroking her face and speaking softly to her before he says this:
Liam to his little sister: Sweet Kathy. No tears. We’ll meet again.
So there is at least one person in that house who cared for Liam and saw his dreams as something worth chasing. We don't know much about his mother, that seems to be hanging in the air. She was crying when Liam was leaving the house the morning so it could be said that she cared for her son and loved him.
And that above statement is foreshadowing to when he comes back as a vampire, that's Kathy who lets Liam into the house. Where Liam had taken the name "Angelus" from. As Kathy says he's come back to her an angel.
His father plays a large overarching role in Angelus's actions, and his fascination with things like "love" and the human condition seem to grow over time. Darla's speech about his dad later on in The Prodigal and the exchange where she's talking about "love", seems to be an indicator.
Now, does this excuse any of Liam's actions as a human? No it most certainly does not. Liam isn't barred from accountability just because he had a rough home life. And this was something that's paralleled with Buffy Summers later on.
However, there is more to Liam that you have to really look at and most people simply refuse to do so. He was a broken man who had toxic and bad coping mechanisms. And the reason why Angel's personality when he gets his ensouled, is so different is because of the weight of his guilt.
Not just for his victims but for what he did to his own family. Liam would never have hurt Kathy or his family in the way he had with no soul. And that arrogant, extroverted man was thrown back into a body where his last memory had been of him following a woman into an alley. A body that had done so much wrong and that crushed him, because for all his faults, Liam wouldn't have done things he had as a vampire.
So Angel wanting to change, seek redemption, be someone isn't just because of his past deeds a vampire. It also plays into his human life as Liam and if Angel ever shanshu'd then he get that forgiveness and second chance to make his human life better than it was before. Do his life all over again.
And that's something he wants to share with Buffy, as she is the love of his life and she gave him hope that he could be someone better. He wants to reach that goal for her and she's the one who gives him that strength.