The only time I negotiated aggressively was with someone who couldn't "read the air" about their prices.
We've had a long relationship since, and still this person can't "read the air" about pricing.
Ironically, by the end of the whole process, I realized this person could probably lower their prices by about 5-10% if they just paid closer attention to their bills and operational efficiency.
There was a hacker news article about it last week. It's similar to "read between the lines."
In this case, I was working with a general contractor to build a home, and I kept pointing out that "newish" houses (10-20 years old) in the area were significantly cheaper, and that his stock of new homes was sitting unsold for a very long time.
Throughout the process:
1 - He sent me to a plumbing and lighting store where everything affordable was something that would go in a very cheap apartment. Everything else was absurdly expensive. We ordered everything off of Amazon for a reasonable cost.
2 - He tried to pass a very large, and obvious, billing error from the electric company off on me
3 - At times he would hint to me about how much money he was loosing floating interest on his unsold homes. These homes had the high-end fixtures where he could have saved about $10-20,000 just buying "nice" stuff at Amazon.
4 - When the house was done, a family architect looked at my basement and told me just how over-built my structural members are.
We've had a long relationship since, and still this person can't "read the air" about pricing.
Ironically, by the end of the whole process, I realized this person could probably lower their prices by about 5-10% if they just paid closer attention to their bills and operational efficiency.