Cricket in England involves, for the most part, a familiar set of venues and a familiar set of routines. If you're a regular attendee, there are certain commutes that you do entirely on auto-pilot - you know where to stand on the train platform, how to time that dash across the junction, who to greet as you mosey through the gate.
But then, every once in a while, a global tournament descends on the country like a scene from Independence Day, and discombobulation is the natural human reaction. Suddenly, you understand what it must be like to be the family cat confronted by a Christmas tree in the living room. Nothing structural has changed in your surroundings, but everything is completely different.
The logos and livery of the ICC's global partners overlay the venues like a Snapchat filter (and at The Oval, that overlaying includes reams of sticky tape to banish all references to the ground's habitual sponsor). Instead of an anonymous trudge from tube to turnstile, there are herds of cheery Cricketeers to guide you on your way, and even bicycle rickshaws for those who fancy a ride.
And then, most tremendously of all, there are the crowds - or, at least, that's how we must hope it will be after an opening-day deluge of fervent Bangladeshi support. Their fans were lured to The Oval in their thousands by the ICC's brilliantly affordable ticket policy, which is aimed most specifically at the neutral contests that might not otherwise be sold out, but has the spin-off effect of eroding England's home advantage when enthusiasm is the decisive factor in making a purchase.
And that enthusiasm was writ large across an occasion that crackled with atmosphere, not least when Bangladesh were batting and going strong. Pockets of green splodges were visible in every corner of the ground, giving the illusion of 50-50 support on the occasions that Tamim Iqbal or Mushfiqur Rahim went for broke, although the actual breakdown was probably nearer 15-20%.
Either way, it was self-evident that this contest was not just another day on the international beat. Instead, it was the start of a tournament with significant ramifications for two sides that have been among the most confident and successful in the two years since the World Cup. And if we, the spectators, felt that step-up in intensity, then what about the players?
What about Jason Roy, England's out-of-form opener, who could not have been given greater license to play his own game if Eoin Morgan had told him to rock up to The Oval in Surrey colours and treat the centre of the pitch like an extension of the Ken Barrington indoor school.
Morgan spoke eloquently after the match about the need to protect his gung-ho batsmen from any seeds of self-doubt, but Roy's innings was a pastiche of anxiety from first ball to eighth - ramped up, you might suspect, by the extraneous reminders that this was no ordinary day. A volley of fireworks greeted his arrival at the crease, before play was held up by a pair of Beefeaters making a late return to their pitch-side drumkits (it just about made sense if you saw them). Shortly after that, the roar that greeted Mustafizur Rahman's salmon leap at short fine leg would not have been out of place in Chittagong.
But it wasn't just Roy who encountered that jolt of reality that accompanies the start of big events. Until Kagiso Rabada vaulted into the top spot amid his demolition job at Lord's last week, Adil Rashid had been the answer to an implausible quiz question - which England player had claimed more ODI wickets than any other bowler since the 2015 World Cup?
Since that debacle of a tournament, Rashid's 60 wickets had come as a result of playing in 41 of England's 44 matches - a tribute to continuity of selection, faith from management and team-mates alike, and a wickedly illegible googly that forced even the best batsmen to second-guess his variations when attempting to take him on.
His omission was not a selectorial bottle-job to rank alongside, say, the axing of Nick Knight in favour of Nasser Hussain for the opening match of England's ill-fated 1999 World Cup campaign, but it came across as a flickering of weakness in an otherwise steely campaign build-up, not least when Morgan attempted to justify it by saying how much Bangladesh prefer facing spin to pace. England were entitled to be cautious when facing a side that had beaten them four times in their previous seven ODIs, including at both the 2011 and 2015 World Cups, but on this occasion, they veered dangerously close to deference.
And while Tamim and Mushfiqur were adding 166 for the third wicket, Rashid's ability to buy a wicket was, in particular, sorely missed, especially while his replacement Jake Ball was being battered for 82 runs in his ten overs - the third time in his last seven ODIs that he has conceded 80 or more. Among England bowlers, only James Anderson has gone for that many that often, but Anderson, in mitigation, did take 13 years and 194 matches to secure such an unwanted record.
With Chris Woakes facing an injury lay-off, and with Ben Stokes' knee a permanent concern, the state of England's seam bowling is the single greatest threat to an otherwise hugely plausible title challenge. If there was a sense in the latter stages of England's run-chase that their batsmen were holding something back in reserve, then the message from their bowling ranks is they will probably need to burn their savings in the coming days. New Zealand on Tuesday, and Australia four days later, are two batting line-ups who are unlikely to permit any let-up in intensity.