You hit the nail on the head (for me) with the last part of your sentence. Sure, away from Leia he still ended up going to prison (though to be fair, we have no idea why or over what at the moment). But the common denominator of all the 'shit' when he was younger, was Leia was there. Away from Leia (say for example with Katie) he was not exactly the same arrogant, self-absorbed asshole. Leia for all their 'bond', also brought out the worst in him, in my opinion.
You'd need to extrapolate that to specific instances. One example might be his first response to seeing Dana, however, read between the lines, try to understand their connection before he left, he knows he can say that to her and he knows she won't take offence, in fact, as seen, quite the opposite. He has the balls (and bare-faced cheek) to say it as it is to her face which no one else will and/or does. I think we will find there are a lot of people around Wollust who actually appreciate his 'straight shooting' as it were. Gina is one for that matter.
He is arrogant, self-absorbed and a bit of a jerk. But he a likeable guy and a
decent guy with it. That's his '
comfortable with you' persona and general attitude. I'm sure most of us have a friends/family attiture very different from say a work personality?
BobTheDuck once mentioned some time ago, if we veiw him as he is with strangers (and not people he grew up with, knows etc), then that is a measure of his true self. So take the garage girl when him and Miru stop for petrol (gas for you weird ass yanks) as an example. How is Willi then towards her? Is he an ass? Arrogant?
No, he isn't, in fact, he's actually well-thought, reasoned and sympathetic.