What personality traits did Walt pick up from his enemies?

Here are the ones I've noticed :

Walt - Traits

Krazy 8 - Sandwich crusts as you mentioned

Gus' dealers - The ability to use kids to his advantage. The dealers used the kid on the bike to kill Combo. Walt poisoned Brock to turn Jesse against Gus and set his killing in motion.

Gus - Ruthlessness. He can kill/have people killed with no remorse. He can be seen whistling soon after Todd kills the kid on the bike showing that he can just shrug it off as something that had to be done. He has all of Mikes guys also killed and it doesn't seem to bother him. I think even if he didn't kill Gus he would of went this way anyway.

Jack - I'm not sure about this one. Jack shoots Hank in the head mid-sentence. Walt shoots Jack in the head, mid-sentence.

Walt - other *Aeroplane crash* - He caused the crash by allowing Jane to die. He kept the eyeball of the teddy bear. Not a trait but interesting.

Gale He ordered Jesse to kill Gale. He kept Gales book even though it was possibly incriminating. Again not a trait but interesting.

Mike Before Mike's demise, Walt would get his drinks a certain way. Mike would always order his drinks with ice which Walt adopted at Hank's some time after dispatching Mike. Also in Felina when he is confronting Elliot, his tone matches Mike's perfectly when mocking Elliot's knife.

I can't think of traits Walt acquired from the following characters :

• Mike
• Emilio
• Gus' guys in the lab

Perhaps I missed something!

Jesse As far as I can remember Jesse only killed Gale and Todd. I don't think you can say that Jesse took any of Gales traits. He became a better chemist but that was probably going to happen anyway. And he killed Todd right before the end of the series so we had no time to see if he took any.

Side note Todd kept the Tarantula the kid on the motorbike was carrying.

I don't think Walt 'picks up certain attributes', as though it were a subconscious reflex: he more accurately mimics qualities he sees as effective throughout his exposure to the criminal world...

There were a number of fan sources that openly (and reactively) sought to quantify this as some kind of conspiracy theory, and Uprox collated the most credible of these together.

I wouldn't go as far as saying Walt automatically takes on other people's traits. More plausibly, Walt recognizes the utility of certain personality traits (ruthlessness, Machiavellianism, Humour) and understands their potency when he finds himself on the receiving end of them.

Remember that he is a scientist, and as such the classification of behavior (whether chemical, atomic or even social) is a familiar method of approach. Walt, in his bubble of relative normality within his Albuquerque Suburb, has simply never met people with such volatile and extreme personalities before (as neither, supposedly, have you or I). When he does come into contact with them, he studies them and recognizes their potential.

Walt only deploys (not neccesarily adopts, which is more permanent) qualities that are useful to him in his circumstances. It is for this reason that he doesn't compulsorily take aspects of people he kills: he just tries to acknowledge what it was about them that made them successful at what they did... until they Crossed Walter White, that is...