Romain Grosjean wasn't his always-smiling self during one dramatic moment at the Bahrain tests last week.
Footage has emerged of the Frenchman angrily thumping the tool benches in the Lotus garage as he apparently discussed the new Renault-powered E22's obvious problems with an engineer.
The footage can be seen here:
Having sat out the first test at Jerez amid recent financial problems, the extent of Lotus' situation with its troubled 2014 car became clear only in Bahrain.
"Of course," Frenchman Grosjean is quoted by Speed Week, "we are still far away from a good performance.
"We need to understand the brake-by-wire system, the new power unit and charging the batteries and in these areas, it doesn't look so good," he admitted.
"But together with Renault, we will work in the next two weeks until Melbourne to improve."
Asked how he will keep his ever-present smile on his face early in 2014, Grosjean answered: "Think of my son."