Honestly, I think the donkeys would be happy if they could carry people like you because you are like a feather :D But like I said, many people are stupid and inconsiderate and they don´t care if they hurt the animals by putting too much weight on them :( It can be the same with horses. It all depends on how much weight they carry and in what conditions the animals are kept. In Krakow, for example, where we lived for some time, there are horse carriages too but there are two big and strong horses for each carriage and the carriage usually carries just a few people (like 3 or 4) so it feels like the horses are comfortable with that. But I know that in some other cities and countries, there is just one horse for the carriage and it´s loaded with many people. That´s animal abuse for sure :( I would just love to kick those lazy fat asses down from the carriage!