They lose control of the kitchen through poor planning. I see a lot of friends who are actually great cooks succumb to this.

They'll think that because something is an easy\small task they can leave it till the end. Little things like taking the seeds out of the lemon slices or carefully picking herbs. A chef knows that a second now (meaning earlier in the day) is cheaper than a second at the end. That's because time crunches exponentially when cooking food. The end is when it's all happening at once, you won't have spare seconds. Any spare seconds you do have will be spent on unexpected problems (chefs assume there will always be unexpected problems).

When that time starts to crunch an hour or so out, the amateur cook will start to get nervous and second guess themselves. They'll tweak the recipe without knowing what they're doing. They'll turn the gas up to get things cooking faster. Or put a steak in the pan before the oil is hot enough. But all they've done is create more pressure on themselves. The temperature is now controlling them instead of the other way round.

In that mental state they'll lose focus. They are no longer trying to create a beautiful dish within a schedule, they are living up to a schedule while cooking a dish. The difference is subtle but profound. Because those jobs they thought were easy at the start now seem like impossible tasks. The seeds can stay in the lemon. The herbs can be not-so-carefully picked, or perhaps just attacked with a large knife on a dirty chopping board. This is also the time when burns and cuts happen. The kitchen is literally turning against them.

At the end it will look like a bomb went off and they'll be standing there, bleeding, mentally destroyed with nothing more to show for it than a bunch of expensive ingredients that are now just scrappy plates of mediocrity and thumb prints.

Hours (even days) before the guest arrive, you've got seconds coming out of your arse. Use them. Savour them. Sure, you've spent a bit more time in the kitchen than you usually would have but that can be a reward in itself. You'll be a better cook for the extra time at the bench, you'll be more thoughtful, more controlled and that will come through in your finished product.

Great chefs are relentless planners and organisers. The phrase 'prepare a meal' should be taken literally and to extremes. Even if it's cheese on toast, be the architect of your destiny.

Remember: Sweat saves blood.