Last time I remember feeling intensely guilty over a specific moment was almost a year ago and was because I ate my ex's(gf at the time) leftovers
We'd been together a little over 2 years but were on terrible terms. I had a ton of resentment towards her, in retrospect over very minor things, and was essentially just waiting for the relationship to end. So we'd barely spoken in the past 2 months, I'd spent the past few months getting hammered almost every night and either ignoring or berating her. It was a fucking mess.
But back to the leftovers. It was April and I was freaking out over taxes, we ran a small business together at time and I was busy trying to find every possible deduction. She went out to lunch with her family, came home and then went to class. An hour or so later, I take a break from taxes to look in the fridge for something to eat and see the to-go containers. I look in them and see fried green beans and honey shrimp. I think "ehh she won't mind if I have some of the green beans" so I have half of them. Then I turn back to doing taxes.
But after a few minutes of frustration I start thinking "fuck this, I'm the one stressed out about this shit and she gets half of everything we make? How is this fair?!? Fuck it I'm eating those shrimp!" So I fucking eat the shrimp.
She got home a couple hours later and walked into the kitchen. I was sitting at the dining room table and ignored her as I typically did. She looks in the fridge, pauses for a few seconds then screams at me "Are you kidding me! You fucking ate my shrimp!" I turned to look at her and she looked like she was about to burst into tears. I mumbled something about leaving her some green beans and she stormed off into our bedroom.
Now at this point I was no stranger to seeing her upset or even causing her to cry. But seeing the look on her face there caused me to kinda have a moment of clarity. This poor girl has the misfortune of being in love with a complete loser alcoholic, who no matter how hard she tries is determined to make the relationship awful. She was probably dreading coming home, knowing I'd be there either pissed off or drunk, with the only silver lining was that at least she'd get to enjoy her leftovers. And I couldn't even let her have that.
I felt like such a piece of shit I immediately drove over to the restaurant she'd been at and ordered the honey shrimp to go. Got home and sheepishly walked into our bedroom carrying the food container. She didn't look at me when I walked in, so I went over to the bed and said "I got you some honey shrimp, if you still want them." She sat up shocked and asked if I'd went out and got her a new order. I told her I had and that I was sorry.
She got out of bed, holding back tears, gave me a hug and I kissed her. She left around a month later and that ended up being the last affectionate moment we shared.
Really though looking back at that relationship all I feel is guilt. Also my current gf had the misfortune of having to hear me drunkenly tell that story on one of our earlier dates lol.