I was laying in bed with a new-ish girlfriend when she noticed some scratches down my back. I bite my nails and as a result I always have little sharp bits at the side of my fingertips, so when i scratch myself it often leaves marks. I told her this and shrugged it off but she then started going a little bit crazy and started accusing me of sleeping with other people. And this was really only the 2nd time I had been in bed with her so the alarm bells should have rung loud enough for me to pick up my things and get out of there and never see her again, but it was late, it was freezing cold out, I had paid for the room, there was a free breakfast in the morning and I didn't really want to split up with this one until my ex girlfriend had seen her.
In the morning she apologised but my pride often tells me I should have just gotten up and walked out or at least thrown her out in the driving snow.