From Aston Villa 1998-99 to Hull City 2008-09, many teams have failed to follow up great starts
Just before Leicester City played and drew with Manchester United, talk started to swirl about whether the Foxes could keep up the momentum they had built after their brilliant start to the season.
Incredibly, a few weeks later, Claudio Ranieri's side continue to top the table and deservedly beat Chelsea 2-1 last night.
They keep defying expectation and as the weeks go on, arguments about them falling away become more and more muted.
But if things go wrong and form goes south, they wouldn't be the first team to make a fast start to a season, only to lose momentum in the second half of a campaign.
I know exactly where I was on September 27th, 2008. I was in a O'Flaherty's pub (now sadly defunct) in Seville, watching on as newly-promoted Hull stunned Arsenal 2-1 at the Emirates when they made a very encouraging start to the season.
That landmark win was the start of a four-game winning run which saw them also beat Tottenham, West Ham and West Brom.
By October 29th when Chelsea halted their momentum, the Tigers had won six games from nine and sat just goal difference off top of the table.
They would only win two more games from then on, although they did manage to just about avoid relegation.
As their form plummeted and the likes of midfielder Geovanni's tailed off, the image that we remember from that season is this bit of ill-advised man-management from Phil Brown:
That rather grainy footage is Brown giving his half-time team-talk on the pitch and in full view of the fans during a Stephen's Day defeat at Manchester City.
Cheeky chappy Jimmy Bullard mimicked it a season later but the damage was done.
Like Leicester, they had played Arsenal and Spurs during their good run, but what Claudio Ranieri's side will hope to avoid is how Hull hit the skids in consecutive away games against Everton and Liverpool (and then a home game versus Man City) and then subsequently failing to recapture any sense of momentum against any teams, stronger or weaker.
Unlike Hull, the Tangerines went down at the first attempt, but by the end of December 2010, they had made a very encouraging start to their first season in the Premier League.
Up to eighth under Iain Holloway (but only six points above the relegation zone), they had enjoyed some impressive away results against Liverpool and Newcastle, while later in the campaign they would defeat the Merseyside club again and Tottenham.
However, their big issue was long runs of bad results in the second half of the season, with a five-game losing streak from January to February and a run of five defeats in six in the Spring.
They also did not manage a single clean sheet at home until the end of April, conceding a league high 78 goals that season with a worsening in that regard (aside from 6-0 and 4-0 humiliations to Arsenal and Chelsea at the start of that season), even though goals scored were plentiful at the other end.
Leicester boss Ranieri has already been offering pizza incentives for clean sheets in an effort to keep his players mindful of balancing their goal threat with some solidity.
It's sad to say for a perennial Premier League presence, but Aston Villa look doomed this season. It's a stark contrast to over a decade ago when they were generally a Top 10 side.
In 1998-99, the Birmingham club were flying in the Premier League and by game 20 of the season, John Gregory's tea, were top of the table, having won 11 and lost just thrice.
However, when you look at the final table, treble winners Manchester United finished 24 points up on a Villa side who had to settle for sixth and even missed out on an Intertoto Cup place.
In the first half of the season, Julian Joachim and Dion Dublin had shared 18 Premier League goals between them. By the end of January to the culmination of the campaign, Dublin would score twice more and Joachim would add a further four.
But that second half of the season was disastrous as they lost 10 of their final 16 matches, a campaign in which they had five players sent off.
Also that season, they did not face one of Liverpool (who did finish behind them in seventh), Manchester United, Chelsea or Arsenal in the league until November, while fourth-placed Leeds held them 0-0 in September.
They also failed to beat United, Chelsea or Leeds home and away during the campaign, beating Arsenal once in a December 13th match, the commentator bills as "title holders against would be champions".
Leicester, though, have shocked a title holder.
The 2013 FA Cup winners might be down in League One at present but when they made their Premier League bow in 2005-06, they made a fast start winning eight of their first 11 matches.
They had lost their opening two games mind you - to Chelsea and Charlton - but their next nine games saw them dispose of teams that did not finish in the Top Six that season.
Paul Jewell's side finally lost their way when they were unlucky to face Arsenal, Tottenham, Liverpool, Chelsea and Manchester United in a five-game stretch and unsurprisingly that quintet of games all ended in defeat.
Fortunately for them, their fast start which left them in the Top Six heading into New Year 2006 meant they had enough points in the bag and managed a creditable 10th in the league by season's end.
Arsenal, United and Liverpool also did the double over them, as did Chelsea.
More recently, the Hammers had a Jekyll and Hyde 2014-15 season. The 2014 part was excellent, winning nine of their first 19 games despite fans' continued suspicion of manager Sam Allardyce's methods.
Contrast that with the last 19-games of the season when they only managed three wins on the way to finishing 12th.
The form, pace and goals of Diafra Sakho and Enner Valencia fueled the good start that put them in the Top Four at Christmas, but a poor January knocked their momentum and coloured their final months of a campaign which eventually saw them part ways from an uncomfortable marriage with Big Sam at season's end.