癖(くせ)にEven though, And yet, Despite

Both くせに and つつ(も) express contradiction, but differ in tone. くせに is a casual expression with a blaming or critical tone, e.g. 知っているくせに何で教えてくれないの？ ('You know, so why won't you tell me!?'). つつ(も) is neutral and used to describe conflicting simultaneous actions, e.g. 危険だと知りつつも行った ('I went despite knowing at the same time that it was dangerous.').

くせに expresses disapproval, similar to 'in spite of' or 'although' in English. In contrast, が is a neutral connecting particle, often expressing contrast (like 'but') or adding information (like 'and'). Unlike くせに, which carries a negative nuance, が is neutral. After な-Adjectives and nouns, くせに requires な or の, while が requires だ or です.

ながらも and くせに both express contradiction, but differ in nuance. ながらも simply expresses two seemingly contradictory states coexisting in a neutral fashion, e.g. 緊張しながらもわくわくしている ('While feeling anxious, I'm also excited.'). In contrast, くせに implies blame or criticism, e.g. 知っているくせに教えてくれない ('Even though he knows, he won't tell me.').

それでも and くせに both express contrast, but differ in tone. それでも is neutral, like the English 'even so'. くせに adds a critical nuance, often pointing out something negative or unjustified, e.g. 若いくせにやる気がない ('Even though he's young, he has no motivation.'), which implies disapproval.

Both のに and くせに express contrast, but with different nuance. のに is relatively neutral, like 'although', while くせに adds a strong negative or critical tone. For example, 頭がいいのにやる気がない and 頭がいいくせにやる気がない both mean 'Although (he's) smart, (he) has no motivation.', the のに version is just stating a fact, while the くせに version implies that his lack of motivation is a negative trait and not befitting of him.

Both くせに and にもかかわらず convey contradiction between two facts, but with different nuance and tone. くせに is a casual expression with a blaming or critical tone, e.g. 知っているくせに何で教えてくれないの？ ('You know, so why won't you tell me!?'). In contrast, にもかかわらず is a more neutral and formal way to say 'in spite of (A)', e.g. 雨にもかかわらず出かけた ('We went out despite the rain.').

Both express contrast, but differ in usage and implication. くせに follows a phrase and has a critical tone, e.g. 知っているくせに教えてくれない ('He knows but won't tell me.'), implying that the speaker is angry at the person. それなのに comes at the beginning of a sentence, is neutral, and expresses simple contradiction, e.g. 彼は真実を知っている。それなのに、教えてくれない ('He knows. And yet, he won't tell me.') with an objective nuance.