So, to mix the game up a bit this time...

After a first play through, where I let my morals guide my characters actions, I try to craft characters that would make decisions either differently from me or, if the former fails, the same decisions for drastically different reasons.

There are a few things I refuse to do, by game:

Origins:
1. I refuse to make Alistair a drunk or dead. He's either a happy Warden, a happy King, or a grumpy King.
2. Can't head cannon a reason to turn down Dog. Even murder Warden will see dog as another weapon he could use to murder.

seem to struggle with making a Warden who would do the Ultimate Sacrifice. Even my first PT with my goodie two shoes, I didn't. Hard to now when I know there are no consequences to the DR.But I'll make it someday.

DA2:
I can't sell Fenris into slavery. I even tried to watch it on YOUTUBE, and I can't even do that. So, I'm incapable, but I also can't see a reason why Hawke would accept him on in the first place just to hand him over later to avoid a fight. My Hawkes never fear battle., psh.


DAI:
1. Can't keep Cullen on Lyrium permanently. Although I did watch it on YouTube.
2. Can't sacrifice the Chargers, which are a definite resource, for the Qun, which are a questionable resource at best, downright a waste of a mercenary company at the least.

There are two romances I question ever doing, Morrigan and Iron Bull, but maybe a million play throughs from now, I'll do them.

The rest would and could be intentionally changed by me each PT.

Like you, I'm trying to get everyone around me to play DA. MIL, Husband, 2nd husband. Husband chose not to recruit Sten his first play through and was actually okay with Isolde sacrificing herself for the blood ritual. Shocking to me from my perspective of what is "natural" to do one plays the first time. I'll be interested in seeing what else he does differently than I did the first time.

Yes, there are some things I just wouldn't do in game, even if Hubby suggested it. I can't see a valid reason for selling Fenris back to Danarius. I watched the scene once on YouTube and that was so upsetting that I know I'll never be able to do it in my game universe.

Oh, forgot to say husband would save the Chargers, another one I would do. I keep telling him he should play it, but he's not really interested in RPGs. He prefers racing or sport games where you can beat your score next time etc. I'm not into those

I'll explore different choices in various playthroughs to see the outcome of some of the more pragmatic options, though my canon ones are always "good".

But I'll have at least one playthrough in each game which is purely "For Eeeevil!". Just to see what those choices are like.

Similar problem: I can't playing for hours with a character, who I can't like at least a bit... I'm terrible role player.

You just have to power through those initial evil choices, it gets easier with time & repetition! 
(Hmm, I suspect this says something about humanity... Possibly something not good.)

ha! I've said this to someone before as well. 

"Just step away and give yourself the evil pep talk and then come back and jump in."

Turning the Mages in to the Templars during the Mercy Quest in DA2 the first time made my heart sore.  The second time, I was like, "Haha!Go back you stupid blood mages!" Maybe it was who I was RPing. First time was a mage Hawke who just thought, hypocritically, any mage that wasn't her belonged in the Circle. SecondHawke was like, "I'd kill them if this quest allowed for it, darn it!" But it could be that I'd already numbed myself to their plight between the two playthroughs.