I personally love when Diablo 3 does a new Season -- it gives me an excuse to create a new alt and/or rebirth one of my current Barbarians.
Diablo 3 has been experimenting with themed Seasons for the Seasonal play for a couple months now, starting last Season with the Season of Greed.
Season 13 of Diablo 3 seasonal play is coming to an end on June 3 with season 14 arriving nearly two weeks later on June 13.
Season 10 of Diablo 3 will be coming to a close June 23, followed by an unusual delay before season 11.
As we await another Diablo 3 expansion announcement, Blizzard is testing out more improvements on the PTR to keep hardcore fans happy.