Trekking through the electronic archives of this newspaper, reading through my reviews for 2016 to find the best exhibitions of the year, produces a high level of anxiety. So much good art! So little space! Whittling down the list, however, is a necessary task, so after much thought and contemplation, I offer the shows that provided me with the most pleasure and the deepest meditation during 2016. I could append a few runners-up that justifiably clamor for attention, but I’ll resist that temptation in favor of a sense of completion and conclusion. The order is reverse chronological.