lines and mown lines not parallel to penalty box line? Split second decision..win some lose some hopefully.
The lines are parallel, they exist to help the linesmen. If they were crooked you'd clearly see them on TV and it would be a huge embarrassment for the club, stadium, and groundsman.
Lines meet as they go into the distance (and things shrink), but also the angle of the lens causes distortion in the field of view which further distorts the lines.
The mown strips are parallel where they coincide with the goal line, edge of the box, and the halfway line, so why would you think they wouldn't be parallel(despite looking parallel to the naked eye) at other points on the pitch