That depends on a few things. If the seller is a builder, they might not take it personally - and it might not hurt your chances of getting the house at a reasonable price.
If the seller lives in the house, they may take it personally. The worst (short of violence) that could happen is the seller can say that you cannot have the house "at any price".
I listed a house for an attorney (calm, cool, collected, unemotional, detached - that's how he described himself). We got an offer in from a buyer at about 83% of the list price. He quickly lost his calm, cool unemotional perspective on selling his house. He instructed me to inform the buyers agent that no offer below full price with this guy's name on it would be presented. He told me that if he offered even ONE DOLLAR below full price, to not even tell him about it.
Be sure that if you're going to make a low ball offer you can live with not getting to buy the house at all.