Williams test and development driver Robert Kubica didn't hold back when asked for his opinion of the team's FW41 at the Circuit de Barcelona-Catalunya.
It was the 33-year-old's first outing in a Grand Prix race weekend since his rallying accident in 2011.
"Coming to Barcelona, I was expecting to be in a difficult situation," the Polish driver said on Friday. "FP1 was even more difficult than expected.
"It has been a difficult session for us with difficult balance," he told Sky Sports F1. "Some we were expecting but not as bad. It was a bit of a shock for me.
"I felt embarrassed when I was driving inside the car, because it was so difficult and I felt so slow in some places. But we couldn't do more.
"This morning, we were slow," he admitted. "But apart from being slow, it was nearly impossible to keep the car on the track.
"That’s something we need to change, in order to make our drivers’ lives easier."
Kubica was at least happy with his own performance, as he continues his comeback from life-changing injuries.
"I felt comfortable," he confirmed. "Although it is difficult to be comfortable in such a difficult balanced car to drive and difficult conditions.
"That is a good test for me," he said. "You need to understand where is your limits and where is the limit of the car," Kubica added.
"In my position when I have to deliver feedback and cannot do silly things, I'm happy by how I reacted to those conditions," he continued. "I think I did what I was asked and I am happy with what I delivered.
The team announced this week that the chief designer of the underperforming FW41, Ed Wood, had left the team "for personal reasons". Kubica said he didn't know what would happen next with the car's development.
"I’m not the right person to go too much into the details," he said. "We know exactly what is our weakest part of the car.
"We've started a project which should help us to understand better, improve it and hopefully solve it completely," he added. “It’s not a question of one day or one month, probably it’s even more, so we have to be patient."
Kubica said that taking part in FP1 had felt surprisingly normal, despite a gap of over seven years since his last race weekend outing.
"For sure it's nice to be in an official session of a Grand Prix weekend but it would be nicer to continue," he said. "I was expecting to have bigger emotions. I had much bigger emotions in the past when I was testing for the first time or even in Abu Dhabi. Although I'm not driving often, it is becoming natural."
Kubica's next FP1 appearance is scheduled to be in Austria, with a third set for Abu Dhabi at the end of the season. Before then, his next outing in the car will be next Wednesday in the first in-season test of 2018.
“We have quite a big programme of understanding some areas of the car and I’m happy to do it," he insisted. "I hope the car balance will be better than today, because if not, it will be a long day."