I make a fair, all inclusive offer (minus government fees which they have no control over). My standard is $1000 below MSRP. If they balk at that, I just walk away. They'll want your phone number so they can harass you later. I keep a spare phone with a minimal $3 a month plan (Ultra Mobile) just for these situations.
As I said above, they are few and far between but there are dealerships out there that will deal without these BS games. You may have to go out of state to find one.
I went to Clermont, FL. It is the auto mall of the southeast. Within a 5 mile stretch of Hwy 50 is every car dealership you have ever heard of, all loaded with inventory. The BS is minimized by the simple fact that you can easily and literally just walk to the competition next door.
I've only purchased two new cars in my life, but both times I managed to minimize the time involved by doing the test drives and chatting on one day, but showing up shortly before the dealership closed on a weeknight to actually do the deal. Yes, the did try to sell me on the all the extras, but they didn't push things either since it seemed like 3 people had to stick around for the whole process (dealer, business paper person, and manager).