Back in the day, the seller put a house on the market and stated the price they wanted for it. Usually, you would go and view it and either offer asking price if you loved it, or you might be cheeky and go a bit under. Then the buyer would come back and they'd meet you in the middle.
These days however, the practice of "offers over" is endemic. Estate agents put an offers over price that is somewhat lower, to tempt you in. Buyers then get stuck in bidding wars, you aren't allowed to know where your bid stands in relation to others, and houses are selling for prices wildly over the OO price.
For example - offers over £350k, house is eventually sold for £390k. Offers over £600k, house is sold for £710k. (Real, recent examples from my social circle)
I'd go so far as to say it's an unethical practice.
The next problem with it is at the mortgage valuation stage. These offers are being down valued. First time buyers don't stand a chance, as they don't have the wriggle room available to cover the shortfall. The seller doesn't care as they can just go back to another buyer who was offering a crazy price. The FTB then goes back into a bidding war on the next house.
I just think house buying in England is just an awful situation.