Random MCU Headcanon #3
Pvt Lorraine, while she did find Steve Rogers attractive, only kissed him because she knew Peggy would see it.
There was an office pool as to when Steve and Peggy would finally hook up and she was about to lose. She figured the two just needed a little push. When Peggy shot at Steve and he gave her that hurt puppy expression, it was worth loosing the pool to see that.