I really don't like people who are ungrateful. It is common courtesy to thank someone for going out of their way to do something for you. Not that I do things for others just to hear thanks, but it is nice to be thanked. Especially if doing something for someone causes the person doing it some form of hardship. Then gratitude is definitely called for. People who have a sense of entitlement and think the world and everyone in it owes them everything are at the top of my list for dislike. I think it is rude and that one day karma will come in and give them exactly what they deserve.