For a man who was initially dropped after just half a season of Formula 1, and then labelled a 'first lap nutcase' shortly after his return, you could have been forgiven for not expecting Romain Grosjean to flourish into the quality driver he is now.

Yet, the story of Grosjean's career is one of redemption: of learning from the errors of his ways, growing up a great deal and become a star who has stood on the verge of F1 wins.

In fact, he admits that if he had not faced his career difficulties and learned from the bad times, he would only have changed for the better if someone had gone as far as punching him!

Ahead of an exciting switch to Haas for 2016, Motorsport.com caught up with Grosjean to reflect on his five-year spell at Enstone, and find out just how much he has grown as a man and driver.

Q: Your two spells at Enstone have come to an end now. Is there one highlight that stands out?

Romain Grosjean: Not really. The first time I drove an F1 car was with Enstone. My first podium was with them, and the first time I led a race. Plus there was the 2015 podium that nobody was expecting. Then leading the Japanese GP in 2013, finishing second in Canada 2012 and Austin the following year. They have been all good memories to be fair.

Q: So how much have you grown and changed in your two stints here?

RG: I think quite a lot – differently in the two cases. The first time I came in F1, I didn't behave the way I should have , but I had no idea of what to do and how to do it.

Unfortunately I was part of the cleaning process at the end of the year, so it was a really hard time. But it made me realise how much I love F1 and how much I wanted to come back – no matter what the price was. So that was good.

And then the second time, I came back in F1, I had to restart with a new image, and show that I was competitive. Then I crashed a little bit too much, with other difficulties.

But from there, I learned to become the driver I am today. It was tough and it was hard, but the team was always supportive and helping me in trying to understand what was not going right. They kept me at the end of 2012, although a lot of people would not have, and in 2013 we got the reward.

Q: Do you think Enstone was the perfect environment for you to be able to learn?

RG: It is always difficult to compare to other teams. If you go to Toro Rosso you are there to learn because that is what Toro Rosso is there for. If you go the first year at McLaren, you have to learn quick. Probably Enstone is in-between the two, which is why I was kept. The performances were really good but on the other hand there were issues. They knew I had to learn – and it was lucky I stayed.

Q: Do you consider yourself fortunate that you got a second chance in F1, when other quality drivers like Kevin Magnussen fail to make it back?

RG: I don't know. I remember February 2010 very well, because I learned on January 31 that I wasn't being kept on at Enstone. I thought I was going to have to stop everything and go to cookery school.

Then I got a phone call from the GT1 Team, Matech, the Swiss team, who asked me if I wanted to drive. I said, 'okay I cannot miss racing, let's go and work'.

I did forget about F1. I was watching the grands prix and thinking it was over. Then the season went quite well, I did a few things with DAMS, and then at the end of 2010 I had an opportunity to go in DTM or try again in F1 via GP2.

So I thought let's try it again. I was lucky that I did a good job with DAMS, and we won the GP2 championship both in Asia and Europe.

That helped people to understand that before [in 2009] I didn't really get the chance. No testing, and straight in the car. The performance was not bad compared to Fernando, three tenths off in qualifying, which is nothing, and in the end it worked.

Q: Do you think the changes you made as a driver and man would have happened if you had been kept on board in 2010?

RG: I would have needed someone close to me to punch me and say, 'what is happening?' It was in Flavio's environment and I didn't really learn to understand F1. It is a complicated world, there is a lot you need to understand and I probably wasn't ready for it and well prepared for it. When I came back I had to be.

Q: Spa 2012 and your first corner crash remains an iconic moment in your career. Did that change you?

RG: It did. It massively did. The Monday after Spa I went to see my psychologist and we started working and trying to understand what was not going right and why I was making the wrong decisions.

In the end it was important – for me personally. Deep down it helped me to bounce back and come back, and I had to show some strong mentality to come back on the grid when some other drivers were criticising me. But in the end, yes, Spa is part of my history, I have learned from it and moved on from there.

Q: But that was not the end of your problems. Mark Webber called you a 'first lap nutcase' in Japan…

RG: That was the worst for me. To me, that was my biggest mistake. It was 100% my fault. I screwed it up…

Q: What is it like when you are facing such criticisms from your rivals. Does it affect you?

RG: It is hard. Especially coming to the start of the grid and everyone looking at you. It was really, really hard at the end of 2012. I was drained. It was really difficult.

Other drivers were playing with the fact that you are under pressure and there is nothing you can do. You cannot move, it was tough.

Then, when I re-signed for Lotus and was kept, it was a big relief and I could start working from there with everything. And through 2013 I started to attack more on the first lap and get back to a more decent level.

Q: And 2013 proved to be a fantastic season, didn't it?

RG: The second half was really good. In the first bit we struggled with the KERS map, which cost us a lot. If we had found out earlier, it would have been a very different season.

The second part was really good, India, starting 17th and finishing third. In Japan I led the race. I was second in Austin, and Singapore I should have been on the podium but we had an engine issue. Then in Abu Dhabi we had an issue in qualifying – and it was almost bad to finish fourth. So it was a great season. The car worked well, we had good developments, but I am driving better today than I was in 2013.

Q. Have the last seasons been tough for you?

RG: Last year yes. A lot. We came from a real high and then went to a very big low. It was the first time it happened to me.

This year it is much different because I am talking about the situation – like engineers not arriving at the track [until late], the freight isn't here, we don't have any cars! You learn about it.

It is a shame because Enstone has shown what we have had and what we can do, and you can imagine when it is back to a factory team like it was in 2005 and 2006, you understand why it was world champion. But right now, it needs some time to restart the new process. You go very quickly from high to low, but to go from low to high takes four or five or six years.

Q. So was it a hard decision to choose to leave?

RG: Initially, it was hard. Initially I didn't think about going somewhere else, but then I met Gunther [Steiner] and Gene Haas, and they explained to me the project.

I think it can be something quite amazing, and it was very straightforward to go and move - and fly with my own wings, see something different.

It would have been nice to be with Renault, a French driver in a French team. But [joining Haas] was the best decision I could do. [Renault] needs a few more years to come back to a decent level, so I may yet come back!