If some animals bother you, then why indulge them? Why play with them?
It's one thing (in slow periods) to flip them the occasional dog biscuit and watch them perform to cue, or demonstrate this to your friends. Factors that make these animals bark and mess themselves also make their behavior more predictable than they themselves are able to see. (This is evident with experience and enough familiar repetitions of behaviors fancied always to be original.) But [adding to recent sound advice here] to engage them and yet complain about their behavior, is unentertaining, not to mention inhumane. Occasionally a difficult animal of consistently ill humor can be an oblique foil for good fun enjoyed by all others -- like a ball on a billiards table used for a carom shot into multiple pockets, technically difficult but gratifying. This is not as good as converting the animal itself to good humor, but it does salvage something. Otherwise though they are usually best left alone. (Suggestion from old animal handler.)
Please remember this when you visit the zoo.