When Brent had caffeine withdrawal when giving up coffee, why didn't he drink Coke or energy drinks? The bet explicitly banned coffee, not caffeine.
He actually tried to order Coke at the Ruby, but Lacey wouldn't let him. It seems the bet was to give up caffeine, since Lacey also offered him decaf, which he refused.
But why did he try to order Coke at the Ruby in the first place? The gas station sells soft drinks too, so he could have just gotten himself a Coke/Pepsi/whatever from the cooler without Lacey knowing about it.
In "Whataphobia," Wanda is asked what she fears, and she can't think of anything. But we already know from "Oh, Baby" that she has a serious fear of dentists. She won't even consider making a dental appointment unless she has an excruciatingly painful toothache, and even then she needs some convincing.
If that dentist appointment went well, she may have gotten over her fear of dentists.