Great advice from A&C!
It reminds me of my very early days flying, where I would invite my friends and neighbours to come along. My neighbour eagerly agreed, asking if his aunt could come along. Sure!
His aunt was a "little person". Though in her sixties, somewhat less than four feet tall. Charming lady! The new thing for me to think about was 45 minutes into the flight, when he said to me that she was having trouble seeing out the window in the back seat - would it be okay if she stood up for the rest of the flight. Hmm, I had not thought about that before! It was a very smooth day, and wanting to be pleasing, I agreed, with the proviso that he hold her [happily robust] trousers belt the whole time, and that she not lean against the door. She enjoyed the rest of the flight very well, and belted up for landing.
Yes, be attentive to your passengers first and above all but safety of flight itself. As level and gentle as possible. No goofing around with anyone in the back seat at all. If a pax really wants the "fun flight", and you think they are up for a few turns, take them separately later.
By the time a pax finally tells you they are not feeling well, they are well into it, and you have a problem to overcome.