Formula One pit stops are some of the most precise and choreographed events in all of motorsports. They take practice to be like that. A lot of practice.
The Mercedes AMG F1 team, like every other team, has spent a lot of time working to make their pitstops faster and faster. At the Australian GP, Mercedes took a lot of time to practice changing tires. If they want to get to sub two second stops, they need to practice like this over and over and over.
It's an art, an engineering ballet, if you will. Truly fascinating to watch.