Thanos really shouldn't be in there he cares a great deal about what death thinks about him as it is his primary motivator in many cases. So if anything it's not so much that he has a F*ck u all attitude as much as he cares too much for the opinion of an abstract being beyond his comprehension.
Sinestro actually cares for his homeworld a great deal as well as for the image of his Sinestro corps.
Wolverine is a big softie underneath it all and has too many warm and fuzzy moments when people break his gruff tough exterior.
Black Adam is probably my 3rd place in the running.
Darkseid is definitely second but his plans have a logic and a reasoning behind him, which is why....
I declare Lobo my champion in this matter. Money is the only thing that talks to him and even then the main man gives no f*cks to anyone... not even... Gawd. Also... RAPID FIRE MINI-NUKES!!! that is all.