You might want to consider a list price which is precise to $100 or $1000 rather than a round number, because the anchoring effect seems to be stronger when a price is more exact. The original paper is behind a paywall, but there’s a summary in this article.
They looked at five years of real estate sales in Alachua County, Florida, comparing list prices and actual sales prices of homes. They found that sellers who listed their homes more precisely—say $494,500 as opposed to $500,000—consistently got closer to their asking price. Put another way, buyers were less likely to negotiate the price down as far when they encountered a precise asking price.
Venting when angry leads to less happiness after the initial catharsis.
In romantic relationships, similar personalities attract, rather than opposites.
The blog Barking up the Wrong Tree also collects psychology experiments of this kind. The posts are often based on single studies, so I don’t know how well-established they are, but it’s often possible to reverse the result and invent a plausible explanation. Some examples:
Spending money on other people makes you happier than spending it on yourself
Heavy TV-watchers are less happy when given more channel options (which itself is an example of the general finding that having a large number of choices reduces happiness)
Chronically ill patients may be less happier if they hope for a cure