Why does 悪く(は)ない give a condescending feeling?


I thought it just meant "It's not bad" but I read some comments from Japanese
people who said that it can sound too condescending or like the speaker feels
superior to the listener. Why is that? In what circumstances could this happen
and when can it be used as a normal reply without sounding rude?

EDIT: after reading the replies, I guess it may be the は that makes it
condescending?




I think it may sound condescending because it sounds like you have the right
to say something is clearly bad. Typically, you can directly say 悪く(は)ない to
someone when you judge their performance/creation as a
teacher/expert/senior/etc. When the creator/performer is not present, 悪く(は)ない
tends to be more often used. (For example it's usually safe to say あの映画は悪くなかった
to your friend.)

And please note that this は is important. 悪くない is relatively positive as
compared to 悪くはない. Sometimes it can mean "it's not bad" in the sense of "it's
good if not perfect", depending on the context and the tone of your voice. 悪く
**は** ない has some negative implication. It means "it's _at least_ not bad" in
the sense of "it's still far from perfect." 悪く **は** ない has clearly different
connotation from "It's not bad", so please use it carefully.




I think it may sound condescending because it sounds like you have the right
to say something is clearly bad. Typically, you can directly say 悪く(は)ない to
someone when you judge their performance/creation as a
teacher/expert/senior/etc. When the creator/performer is not present, 悪く(は)ない
tends to be more often used. (For example it's usually safe to say あの映画は悪くなかった
to your friend.)

And please note that this は is important. 悪くない is relatively positive as
compared to 悪くはない. Sometimes it can mean "it's not bad" in the sense of "it's
good if not perfect", depending on the context and the tone of your voice. 悪く
**は** ない has some negative implication. It means "it's _at least_ not bad" in
the sense of "it's still far from perfect." 悪く **は** ない has clearly different
connotation from "It's not bad", so please use it carefully.

