Nick Kyrgios is almost always worth paying attention to.
Whether he's slamming 42 aces, hitting the ball at up to 136 mph and saving all five break points faced, as the 15th-seeded Australian did during a 7-6 (3), 7-6 (4), 6-7 (5), 6-3 victory over Denis Istomin of Uzbekistan in Wimbledon's first round on Tuesday.
Or accidentally hitting a ball girl with one serve, causing her to cry and leave the court, as also happened at the All England Club.
Or arguing with the chair umpire over all manner of matters, possibly important or not.
Or barking at his guest box, at one point telling those in it they might as well not be there at all.