Extremely negative feedback
and active resistance
against something. The term implicitly admits that the objectionable misfeature
is being pushed onto the user.
"Pushback" was used by a Microsoft salesdroid at an Office XP launch, speaking of Clippy: "We had a lot of pushback from our customers on that one."
Pushback is also used to describe a possible defense against a distributed denial of service (DDoS) attack, in which the router nearest the target tells its upstream colleagues to rate limit the traffic to the target. They can then tell their colleagues to do the same, and eventually the message is pushed back to the friendly router farthest from the target.