why do people put a date on Jesus's return? [Spirituality & Religion]

one youtuber is convinced that God will come back on July 17th. she said God told her that. I'm sure she genuinely loves God but since no one knows the hour or day he's coming back I'm kinda skeptical about it. I mean may be he will come back then you never know. I just don't know why she's putting a date on his return.