What would bring YOUR Shepard to tears?

In all three games, Commander Shepard is very good at keeping much of his/her emotions in check, regardless of the choices we make for the character. But this raises a question:

What would be the one thing that could occur in the trilogy that could/will actually bring your Shepard to tears?

It could be anything. A specific encounter, the death of a close squad-mate (possibly even a love interest), a failure to accomplish something, etc. Just if there is one thing that you feel would really deeply hurt your Commander Shepard on an emotional level, what would it be?

⁽*^Sidenote*^{: Yes, I'm well aware that pursuing a romance with Thane in 2, and then seeing his tapes in 3 in the Citadel DLC is perhaps the only case in the series where Shepard is in tears, but what other incident would it be for YOUR Shepard?})

Example: "My Shepard romanced Tali in 2, and started rekindling his relationship with her in 3. But her suicide in 3, if the Geth wipe out the Quarians, would break him to his core. I'd imagine after the Rannoch mission, he'd quietly go to his cabin to be alone and break into tears (similar to the scene in Saving Private Ryan Capt. Miller breaks down after Medic Wade's death)"