I don't intend to list those traits here, as I am at present Lee J. Cobb.  Alas, I couldn't begin to give you a list of personality traits I associate with the actor, either, except for a few of the most prominent ones he's projected in some of his movie roles.  And those I can't provide objectively, because I've assimilated them as my own.  I can't give you the roles that affected me even, which carried those traits into my imagination.

I can say this:  Something happened when I rolled out of bed this morning.  I coughed a little, sniffed assertively or cleared my throat a certain way and suddenly I was Lee J. Cobb.   All the while I did my morning chores - fed the cats, cleared last night's dishes from the kitchen counters and fixed my coffee and whole-grain rolls, and later spreading cracked corn for the chickens and opening the coop and holding a handful of cracked corn for a couple of roosters and two or three hens that feel familiar enough with me to peck out of my palm - I was Cobb, the way I tilted my head a certain deliberate way and squinted one eye, opened my mouth a little and curled my upper lip in a half grimace.  

I did none of this consciously.  I recognized the ticks as they were happening.  I could see Cobb's face mirroring mine as I was doing them.  I felt from inside that I was looking out through Cobb's eyes, that my face was Cobb's face.  

These roles, or visages or personas or whatever they are that turn me into someone else for a brief spell are not deliberate.  I can't tell myself I'm going to be Lee J. Cobb now or Heath Ledger as The Joker or Clarke Peters in The Wire or  Robert Duvall in anything or Frank Sinatra as the beleagured Maj. Marco in The Manchurian Candidate, Prof. Irwin Corey or author Stephen King or any of a myriad others. It doesn't work that way.  It's not a think therefore I am phenomenon.  Just the opposite.

I feel therefore I am.  It can't be a conscious thing, because I'm aware I'm not projecting this image to anyone else.  Nor are the personas of some of these temporary role models known to me beyond a rough but definite impression they leave on me in their brief and narrow exposure to my preception.  Irwin Corey, for example, I know only from comedy skits I saw him do decades ago, rambling on and on with big words and multiple non sequitur clauses all of which together made no sense whatever.  What pushes my buttons with Corey is simply the image of his crazy/happy/putting-you-on face.  He looks to be completely comfortable with who he is and what he looks like.  

Duvall has a similar face and persona that goes with it.  He always looks to be secretly enjoying himself no matter what travail he might be struggling with.  King conveys a joie de vivre through his writing - at least he does in the most recent book of his I've read, On Writing - and this enthusiasm is reflected in his face, especially the eyes, which signal the mischief he no doubt feels scaring the bejeebies out of readers with his tales of suspense and horror.  

With King, whom I haven't read much, I think the effect is mostly an echo of my identifying with him as I absorbed On Writing, reassured to know that such a highly successful writer has struggled, and presumably continues to struggle with his lonely craft in ways I know only too well. 

The Joker?  Well, if you must.  Ledger expresses so magnificently in this role the cold, brilliant, maniacal rage of someone pushed irretrievably over the edge, yet who remains in the game, for better or worse.  

I've just noticed most of these models I've mentioned  are not happy people, at least not as I'm recalling them or the roles that stay with me.  And none are chuckleheads, pretending everything is their own private hoot.  They've all known hardship and sorrow, but there's a grit in them, in some more evident than others, but enough in each to resonate with the darker memories that leech up out of my bones from time to time, most often when I'm feeling alone and somewhat desolate.  That's when a certain tilt of head or snort or cough, stubborn grimace or flash of absurdity puts me smack dab in the middle of somebody's head, gives me a glimpse of the world I know to be true to a degree and not as bad as I'd been thinking a moment before.

I feel, therefore I'll get by.