I actually thought she would have been turned off by him kissing her like that, because it was inappropriate and it was something that Don would never do.
Yeah but remember last season or was it season 3, the night Don and Peggy got drunk together at the office and Peggy asked how come Don never came on to her, it bothered her that Don smutted out every women he came across except Peggy. It might not even be that he came on to her but the fact someone finally did, it made her feel special. The funny thing is, IMO the only reason Don has never come on to Peggy is because she is the only female Don actually respects. The reason he is so cold to her at times is because Don sees himself in Peggy.