Rachel is correct on her stance about sex ed, and articulately expresses the truth that many intelligent adults know: celibacy just does not work for teenagers. Contraception is a more effective teaching tool. By putting herself out there as a sexually viable candidate, Rachel is offering something to Finn that Quinn is not giving him. Taking into account his racing hormones, it is no wonder that Finn goes for it. Their kiss probably should not happen. Not every teenager lets his or her biological need overrule morality and sense. But in the charged situation that Rachel sets up, it is not surprising that a kiss occurs. Rachel is ruthless in getting what she wants. At this point, while Rachel and Finn's growing attraction is nice to watch, if Quinn were not such a witch, viewers would be rooting for her.
A memorable Finn line, highlighting Glee's trademark tongue in cheek humor, comes after Finn decides he needs a break to feed his hunger while rehearsing with Rachel. She has a picnic spread already set up just feet away from them and offers him food, and he says, "Wow, I was wondering what that was all about." Observant much?
Keeping with the theme of aggressively trying to offer men stuck in a bad situation a "better" option, Emma makes a play for Will. Her staying and helping him clean during his part time janitorial job can not be mistaken for anything else. The difference is, soon after Ken is there to offer Emma sane, sound advice, and she is in her right mind enough to take it. While Ken may not be the man for Emma, she should move on and give someone else a shot. Will is not available, and as long as he's been with Terri, she doesn't want to be the rebound, should he leave his wife, anyway.
Terri is actually sympathetic in "Showmance." She learns her pregnancy is hysterical, not real, and she decides to tell Will. She cooks him a special dinner and waits up, lighting candles and being as caring as possible to try to soften the blow. The decision to lie comes quickly, and is clearly seen in Terri's eyes. Will is too excited about the baby for her to dash his hopes. It's a moment that shows how much she cares for her husband, and proves how great Gilsig is as an actress. Terri almost immediately regrets not telling the truth, as he hugs her to him. In a rare glimpse, we see that Terri does love Will, and their romance is real. Her mistake, then, is not the initial lie, which is told from a place of love, but carrying on the charade for months afterwards.