newspaper his newfound outlook also helped cope with his seemingly endless injuries.
They have cost him an early end to the 2015 World Cup and missing the British & Irish Lions Tour of New Zealand two years later.
Since then, Vunipola has amazingly broken both his arms on two occasions apiece - the most recent in January this year.
He is understood to have been a disruptive voice at some meetings during and before last year's World Cup with The Times citing one at the pre-tournament training camp involving forwards coach Steve Borthwick.
His contrite attitude was sparked by visiting south America on a charity visit in December and witnessing children enjoying themselves playing on the streets despite the daily hardships of their lives.
"I have talked to people that it affected," he said of those who felt the lash of his tongue in the national set-up.
"It's hard to admit it sometimes and tell people around you that you are wrong."
Lockdown brought the English season to a halt in mid-March but with Saracens already relegated due to their persistent breaches of the salary-cap.
They resume their Premiership campaign against highflying Bristol Bears next Saturday whilst the defending champions face a tough European Champions Cup quarter-final against Leinster in September.
Vunipola said the period also taught him some hard home truths about making efforts even with people who he had not felt warmly about before.
"I'm 27 but my wife thinks I still act like I'm 21," he said.
"I'm going to try to set a better example to myself and everyone else.
"Obviously there was the episode where we got in trouble for having a few coffees with the boys (and flouting lockdown rules).
"From my point of view it was about trying to get around people I enjoy being around, but also challenging myself to hang out with people I wouldn't necessarily hang out with, to broaden my horizons.
"I think that put me at ease when it came to my injuries."
Vunipola said the biggest benefit in this change of attitude has been a marked improvement in his relationship with his older brother, prop forward Mako.
"I think Mako can see there is change in me. We talk a lot more," the back-rower said.
"Before, me and him didn't really get on and that was my fault because I would never make the effort, I would never listen to him because I thought I knew the crack.
"We were very competitive with each other but maybe we didn't support each other as best we could and that is definitely something I felt I didn't do for my brother."