I've been wondering if the reason the curse didn't hit all the right targets - i.e. people who loved Barnabas - is that the curse, being only a curse and not human, was thoroughly befuddled by the whole concept of love and decided that the safest course was to go after only those people who said right out that they loved Barnabas. Angelique did, so she was doomed, but Joshua didn't, so he was in the clear. I wouldn't be surprised if Trask and Abigail each at some point declared that they loved Barnabas, because they knew that as Christians they loved their neighbors. And Nathan...who knows what Nathan may have said in the privacy of his boudoir? Poor, timid Rachel never said she loved Barnabas, but she did kiss him on the cheek once, and by then the curse had enough experience to know that this could only mean love. Julia said she cared about Barnabas, which probably had the curse saying, "Dammit, what do I do now?" (I like the thought of a curse cursing.) But before it could make up its mind, Angelique put it out of its misery.
PS Spellcheck doesn't like Trask. Smart spellcheck!