If one chooses to sit in one of the last rows, there are less people behind you watching you as you act like a crazy monkey taking pictures of everything and everybody.
Also, often the last rows are less crowded, giving you an enhanced option to get a row with an empty middle seat. If you are really lucky you have two rows to yourself enabling you to switch between port and starboard.
Downside is, that the hot exhaust from under-wing engines blurs downward views (for a limited viewing angle).
Therefore, sitting in front of the underwing engines would be the better position, but, as VonRichthofen
wrote, the front of the cabin often is no option with a discounted Eco-Class ticket.
Carpe diem ! Life is too short to waste your time ! Keep in mind, that today is the first day of the rest of your life !