I, too, feel your pain. I no longer plan trips for others unless those others are under age and in my control. I remember one trip where a family member was hesitant to go and would only go if I promised he would have a great time. In my exuberance I told him I promised. The whole trip he would taunt me saying "I'm not having fun right now. Do something." I was really over him and after a couple of days I let him have it. Unfortunately, it soured our relationship and we have never really recovered from it. I decided then and there I would never put myself in the position of being responsible for another adult's happiness. They can choose to have a good time..... or not. Its up to them. I have also had occasions where the idea of Disney sounds good, but the reality is a totally different thing. We had a trip with friends who swore they wanted to do rope drop every morning and hang with us the whole day. I believe their intentions were right. The reality was that their entire family needed a LOT more sleep and had a lot less stamina than mine. By the 3rd day they were sleeping in until 10am and going back to the hotel right after dinner. Later the Mom told me that Disney was absolutely overwhelming for them and they had no idea how tiring it would be. They were used to beach vacations where they just sat around all day.
