Issued when a player exceeds the 25-second shot clock between points. First offense is a warning, second costs a first serve (you go straight to second serve), and it can escalate from there. Introduced to speed up play because some players were treating the baseline like a meditation retreat between every point. Nadal's pre-serve routine has been a recurring topic.
"The shot clock hits zero. Time violation, warning. He was still adjusting his headband."