How to get the start and end times of a day

I am surprised to see how an incorrect answer received so many upvotes:

The correct version would be as follows:

public static DateTime StartOfDay(this DateTime theDate)
{
    return theDate.Date;
}

public static DateTime EndOfDay(this DateTime theDate)
{
    return theDate.Date.AddDays(1).AddTicks(-1);
}