I have a hard time relating to any of the sins. The main reason being is that each of them so far is an impossibly good... Its not like they are just regular nice guys, they suffer from being overall too kind, they would throw their lives away to save someone without a second of hesitation. Add to that there is the fact that meliodas is a 3000 year old demon who betrayed and sealed his clan apparently to save humans and whatnot, king is a fairy king who has little regard for human affairs overall, diane is a giant with little regard for human affairs who for whatever reason has been a child and then a teenager for what seems to be at least 700 years (which is most of the lifetime a demon has), ban kinda stopped being human when he drank immortality just to see if something good ever happens to him only to then desperately want to die because he lost elaine (so... he was mauled by the abstract concept of irony I guess), gowther is something between ultron and skynet but with rapey tendencies, merlin is... merlin I guess and escanor is either the hulk with vanity issues, a wimpy kid, and perhaps as an old man he will be kinda sage like... To add to that the sins do not make them more relatable considering that so far they did not commit them. For whatever reason they simply choose to perpetuate the believe that they are the criminals everyone thinks they are when in reality they are the most extreme opposite of that. Its not like they are making themselves out to be martyrs... they simply don't care about this. I guess its plausible that in their eyes human life is so fleeting that its simply not worth their time to clear this up.
At least for me their lives are so removed from that of a human, their issues so different, that its kinda hard to relate to them. Even elizabeth who is a human suffers from having too much empathy thus being unable to heal herself. She only healed herself "for meliodas". The "human" side to the story and maybe even foil are usually either hawk, a magical pig, and perhaps the human holy knights, who while superhuman seem to fall considerably short of the sins in terms of power and kindness.