They make a good case...this is a very personal thing, though. I've discovered it's the viewing experiences that you don't expect to tear up to that are most likely to leave you a sobbing wreck. Herewith my examples:
1. Silent Running
This obscure hippy-dippy early 70's eco-sci-fi flick starring Bruce Dern was the first movie that ever made me cry (post-child, I mean. Everybody cries at movies when they're little.). Watching it late night on TV and the last scene with that damn little robot watering plants and that damn sappy ballad comes on and...water works. Shit.
2. Lonesome Dove
The original 1989 miniseries, which, by the way, still holds up like gangbusters, best miniseries ever on network TV. My parents taped this for me (on a device called a "VCR") because I was on a summer camp trip when it aired. I got home and watched the whole thing straight through on a Saturday. When (SPOILER) Gus dies in hour 5...shit.
3. Toy Story 3
Most recent. What? Like you didn't.
Feel free to share your thoughts. This is a no-judgements environment.