Earlier quoted context omitted.
agree. Especially with #3 "understand what boss wants" From the way OP phrased the question, it sounded like the OP felt the manager "owed" the OP. As in, OP feels going to the conference is a must, "a given", a "constitutional right", and that the manager "wronged" him by not letting him go. It's a very childish way of viewing the world. As in, I deserve to go to Disneyland. My mom won't let me, so I will now get a…
If the OP really wants to give a talk is because they are seeking for some kind of recognition or ego booster. This sounds very self centered and narcisistic.
Being weird and shitty and making claims of "narcissism" should come with evidence, or at least an argument.