are all completed sales automatically positive?

[mikalvon]

i noticed when you go to make review after a completed sale there is no other choice than positive

[buyselljack2016]

Feedback left for buyers can only be positive.

[lamber9347]

As a seller you can only leave positive feedback for your buyers. 

As a buyer there are options to leave positive, negative, or neutral feedback. That remains in place for all buyers. Best of luck to you....

[mikalvon]

my point is if a buyer has his feedback setting as private a seller would never know anything negative  about this buyer because you cant give a negative rating... right?

[eburtonlab]

if a buyer has his feedback setting as private a seller would never know anything negative about this buyer

Buyers can only receive positive feedback, so it does not really matter if the buyer's feedback is private or not. Sellers can check the buyer's feedback left for others if the buyer's feedback is not private, though.

Some sellers try to leave positive feedback with a negative comment, but this is against policy and the comment is subject to removal and the seller can get an account defect for that.

Feedback allows buyers to judge sellers; it does not really work the other way around.