Me: Based on your user stories and requirements you submitted in May we plan to deploy the next major software release in August.
Client: OK, great!
Me: Looking at the feature request you submitted in mid-July, we can get you that feature by mid-September.
Client: Wait, what happened to August?
Me: You asked for more to be added, and it will take a month.
Client: You gave me a timeline, and I expect you to stick with it.
You gave me a feature list and I expect you to stick with it too, jerk.