Some of the most common issues are door that do not open and close smoothly or mechanical
items that are louder than they should be, often because they are not tight enough. Other common issues can be pipes that leak or that have not been turned on.
Obviously, after a period of time, you should have found anything that was not right with the new house and any problems would then be attributed to normal wear-and-tear.
The point where this crossover from the builders responsibility to yours is what must be clearly set in the contract, otherwise fights can and do arise.