Yeah, I agree, he’s a really angry guy. I got the impression that OT Vader doesn’t often care about things - the opinions and failures of random Imperials are little more than nuisances to him - but when he does care, like with Luke or the Death Star plans, he really gets passionate about it.
That was actually one thing that irritates me about his ROTS portrayal. He starts his Sithening with the very appropriate and emotional “What have I done!?” and “I can’t live without her!” but then he pretty much immediately starts doing a bad OT Vader impression (“Yes, my master…”). I feel like the loyalty that he demonstrates in the OT would’ve come from years of Palpatine wearing him down, in line with “It’s too late for me, son… You don’t know the power of the dark side.”, rather than just being something he adopted immediately. Oh well. At least we get a bit of angry Vader on the landing platform, and after he gets his suit, even if he still has a few weird lines in there about lectures.