Stupidity: The problems start when they try to get the man into the house without Jackie noticing. It's a bit odd that their first idea is to put him in Martins car, since that's the car they're going in. The best option would be to go through the front door and up the stairs since Jackie was going through the living room. As concerned as Martin is about Jackie finding out about the oil on the carpet, I don't think he would forget about the front door.
Stupidity: The whole episode revolves around Adam bringing his girlfriend Emma to his parents' house to meet the family, but problems start to arise when Emma's sister begins texting Adam pictures of her in her underwear. Adam is extremely bothered by this and attempts to make sure Emma doesn't find out. When everyone is at the dinner table, Adam decides to leave his phone out on the table even whilst he continues to receive texts from Emma's sister and the family begin to comment on it. If Adam was so concerned about Emma finding out about the texts, he could have easily turned off his phone and put it back in his pocket, but instead decides to leave it out on the table and switched on, only drawing more suspicion from Emma. Even when the little girl arrives later and asks to play with his phone, Jonny reaches out to grab it, but all Adam does is take the phone off the table so Jonny can't reach it, and then immediately puts it back on the table again.
Suggested correction: Adam knows Jonny is joking with him, as he usually does. As for Katie taking his phone he didn't expect her to. They have all seen Adam's reaction when getting the messages and he is trying to cover something up. Doing anything to prevent anyone seeing his phone more would arouse suspicion. Personally I don't understand why he didn't just explain that Emma's sister has been sending him pictures and ask Emma to talk to his sister. He didn't do anything and loses someone he liked for no reason.
I was mostly referring to the scene where they are sitting at the dinner table BEFORE Katie arrives. Despite the fact that he kept receiving texts from Emma's sister and was growing more concerned and everyone begins to comment on it, all he does is put it back on the table, switched on, ready for another text to come through, which makes everyone further suspicious. There is no reason at all why he couldn't just turn off the phone, put it back in his pocket, and lowered suspicion.
A better idea would be for him to have told Emma after it happened the first time. I'm sure that saying "your sister just sent this to me for some reason. I'm quite uncomfortable. Could you please ask her why she's sent me this?" would have sufficed. He creates bigger issues by denying anything is happening.
