Playing as a good person in Skyrim is almost impossible. There are very few non lethal alternatives in the game, Calm is a great spell that can help you to play as a pacifist, however it is limited by the narrow corridor that is the Skyrim Quests. In many of the quests I have no option other than to kill said person. Although there are times in which I can persuade a person to give me an item, or to leave, that option is almost always impossible as the speech options are few and far between, followed by the lack of progression that the Speech skill can go through due to limited chances to actually raise it.
I disagree. I play as a good-sided character (310 hours, level 38) and I don't find frustrating situations that force me to do evil deeds... and I don't exactly know what you mean when you talk about persuading someone to give you an item, "or you kill them". Not asking for spoilers either, but I'm not sure right now if I found myself in that situation... Of course I've been asked to do lots of things about stealing or killing, but I ignored them all.
The same I don't pick any item that is not mine, even if it's flagged white (barres on streets, items on friend shops, etc.). And if I get asked to take something from someone, I only take the quest if I think it's fair. I mean, I may disagree with a situation so I just don't take the quest, because I feel the "victim" doesn't deserve to be either persuaded or intimidated. I don't have to "beat" all quests. At least not with this char. For example, someone asked me to bring a copy of a book. I finally found it, and even if it was there, ready to pick up, it belonged to someone else, so I didn't (it also has the "steal" text on it). This is an example of being able to do something (as player), but also follow the rules I decided for this char.
This character is also good at speech, so depending on the quest I can either intimidate someone (if they deserve it) or try persuading, but if any of those doesn't fit my "good-sided" character, I just bribe, or maybe even exit the conversation and ignore that quest. Just a way of let it be.
You talk about the Calm spell... well, I don't use magic neither read magic books with this char (it's just an archer), but I have a shout that calms wild animals. I use it with bears, sabrecats and some other wild animals which "home" I invade while traveling, that I understand have nothing to do with me, so I also let them be, and this also gives more immersion to this good-aligned character.
All this with my current char. The next one could be all the opposite, and I will have same fun doing other things. But it will be different stuff, that fit with that char, but doesn't with this one.
Anyway, even if you want to be 100% good, it's the medieval era. You CAN be good, but smart at same time. And remember you can always ignore a quest if you feel it doesn't fit the char, even if you agreed to do something and the quest log is there waiting. As far as I know there is no phase on the MQ that forces you to be evil, so at worst you will just end up with several unfinished side quests on your log.