What is the worst misconception about this deity that you have encountered?
As today is the observance of Antinous’ death, I will keep my remarks brief, especially since my answer involves topics that have already been covered in other posts. The worst misconception about Antinous is that he was deified by the will of Hadrian, and thus, by extension, is not really a god. Today we commemorate the encounter with the Nile waters that meant the end of his mortal life and the beginning of his godhood.
Tied with this notion, which appears in supposedly authoritative sources about the ancient world, is the misperception that he is a god of gayness, as if most of the male gods of Greece (and many other cultures) were not queer or bisexual in 21st-century terms. Antinous is a god, truly; he was and is the lover of Hadrian, but Hadrian is not his only beloved, nor are they all male.