Eddie Jones enjoyed watching England toil against Samoa before wiping the slate clean ahead of a bid for a record-breaking 2018.
A much-changed England scored seven tries in a 48-14 victory at Twickenham, following up the autumn successes over Argentina and Australia.
But there were 31 minutes between points for England either side of half-time before a late flurry put a gloss on the scoreline.
"I probably would've been disappointed if they didn't struggle," said head coach Jones.
"That's the sort of examination we wanted, particularly after playing Australia.
"When you're playing against a side you're supposed to beat by a big score... the mindset you need for that sort of game is something you only get by experience.
"We started the game well and then thought the game was going to flow and going to be easy.
"We want to find out these things now, what players struggle to do. And then we can help them and they can help themselves fix it.
"You don't want to find these things out in the 60th minute of the game against Tonga in Kobe [during the 2019 World Cup opener], that some players aren't up to it."
England finished 2017 with nine wins from 10 games - March's loss in Ireland Jones' only defeat in his 23 games in charge.
The squad will reconvene in the new year ahead of the Six Nations, when England will be seeking to become the first side to win the championship on three successive occasions.
"I'm excited about the Six Nations as we've got a chance to create history," Jones added.
"We reassemble in eight weeks' time. The next eight weeks is a great opportunity for players to show how much desire they've got to be part of a World Cup-winning side.
"A lot of it goes out the window because some blokes could now not show that they've got the desire to work hard, so we start again.
"That's the great thing we've got here, we've got great competition."
Jones relishes the competition from the Six Nations, which begins for England in Italy on February 4.
"Every side wants to beat us," he said. "Whether they're playing here at Twickenham or away, this is their big game of the Six Nations.
"That's a great thing for us - we're put under enormous pressure every game we play in the Six Nations."
England led 22-7 at half-time through tries from Mike Brown, Alex Lozowski and Charlie Ewels, with Piula Faasalele responding for Samoa, who also scored through Chris Vui.
Elliot Daly scored the hosts' fourth and sixth tries, Henry Slade added a fifth and Semesa Rokoduguni a seventh. George Ford finished with 13 points.
British and Irish Lions hooker Jamie George made his first England start after 19 substitute appearances, with England captain Dylan Hartley among the replacements. That scenario demonstrates the level of competition Jones wants.
Jones, who described George's performance as "productive, very good", added: "There's ongoing competition between those two. And we love it.
"It's not like an election. You don't have one day and it's decided."
Wasps lock Joe Launchbury suffered a shoulder injury and Leicester wing Jonny May concussion in a physical battle after which Samoa head coach Titimaea Tafua rued costly errors.
Tafua said: "They played well. Some of our mistakes cost us."