Being a goalkeeper is never easy. Their heroics are often eclipsed by those much ahead in the playing field, and they are rarely in the reckoning for the best-player prizes apart from a few glorious exceptions.On the other hand, they can also be easily thrown under the bus for committing mistakes even when the whole team wasn't up to scratch in a particular game.So essentially, a goalkeeper's job is largely thankless. But there have been quite a few goalkeepers in the Premier League this season who committed unforgivable mistakes and cost their side some valuable points.Let's look at each of those six moments from the season thus far.#1 Dean Henderson (Sheffield United) vs. Liverpool | Sept. 28, 2019The Manchester United loanee also endured the wrath of the Red Devils faithfulsSheffield United could have been the first side to take points off Liverpool this season had it not been for Dean Henderson's clumsy blooper. The Reds struggled for a vast majority of the match at Bramall Lane, even failing to muster a shot on target until the 69th minute when Giorginio Wijnaldum tested the English shotstopper.Disaster for Dean Henderson!Heartbreak for Sheffield United! 💔Georginio Wijnaldum's volley goes straight through the Blades goalkeeper to gift Liverpool the lead... pic.twitter.com/CQvAPgTtwn— Football on BT Sport (@btsportfootball) September 28, 2019The Reds midfielder tried his luck from distance and shot straight at Henderson, but the Blades 'keeper spilled the ball through his legs and allowed the visitors to steal all three points. As costly as his mistake proved to be, he has since gone on to revive himself with a series of solid showings and was also in the reckoning for a spot in England's Euro 2020 squad.#2 Roberto Jimenez (West Ham United) vs. Burnley | Nov. 11, 2019Jimenez had a forgettable day at officeThis has to be arguably the worst performance by a goalkeeper in the Premier League this season. Roberto Jimenez can hold himself responsible for the humiliation at the hands of Burnley, who were literally gift-wrapped all the three points. Post-match reactions also showed how the fans were baying for his blood.West Ham without and without Roberto Jimenez starting in the Premier League this season -- The goalkeeper has left the Hammers to join AlavesFor more player stats -- https://t.co/XO5EK8fhcR pic.twitter.com/THZwKMkbHs— WhoScored.com (@WhoScored) January 20, 2020The Spaniard's terrible pass to his own teammate at the back allowed the Clarets to pounce right in and double the advantage. And if that wasn't embarrassing enough, he later went on to punch a corner kick into his own net. Jimenez attempted to palm the ball away, but awkwardly ended up scoring an own goal to cap off a torrid evening.#3 Alisson (Liverpool) vs. Brighton and Hove Albion | Nov. 30, 2019Alisson was shown a straight red for thisAlisson and errors aren't normally uttered in the same breath, but on this particular occasion, they were. Make no mistake, the Liverpool 'keeper has been absolutely phenomenal for his side this season, even assisting Mohamed Salah for his winner against Manchester United, but things just didn't go as planned on that evening against Brighton.Alisson was sent off for Liverpool after handling the ball outside the box ❌Adrian came on for the resulting free-kick 🧤 And then this happened 😲pic.twitter.com/pXQOQB80pH— Goal (@goal) December 1, 2019The hosts were 2-0 up and cruising towards another routine win when Alisson's moment of madness earned him a straight red. He charged out of his area to block Leandro Trossard, but a blatant handball instantly sent him off, reducing Liverpool to 10-men and also handing the visitors a free-kick from a good position, which Lewis Dunk intelligently dispatched.#4 David De Gea (Manchester United) vs. Watford | Dec. 12, 2019De Gea spilled an effort which he honestly should have savedIt has been legitimately asked whether David de Gea can still be considered a world-class 'keeper. The Spaniard is committing more mistakes than ever and has cost Manchester United at various points in recent seasons. He also came under fire for poor performances at the 2018 World Cup with Spain, and looks like he still hasn't recovered.6 - Since the start of last season, no player has made more errors leading to goals in the Premier League than David de Gea (6). Gifts. #WATMUN pic.twitter.com/RIpNYWZYi5— OptaJoe (@OptaJoe) December 22, 2019Watford's shock 2-0 win over the Red Devils saw De Gea let slip Ismal Sarr's effort for the opener. He appeared to catch hold of the Senegalese's header, but somehow inexplicably, couldn't and gifted the Hornets a priceless opener. It was yet another howler that made De Gea look like a Sunday League player. Bizarre for a goalkeeper of his class.#5 Kepa Arrizabalaga (Chelsea) vs. Newcastle United | Jan. 18, 2020The Spaniard erred at a crucial momentThe jury is still out on Kepa Arrizabalaga. He has had issues living up to the 'world's most expensive goalkeeper' price tag ever since he signed for Chelsea in 2018, as the Spaniard has constantly come under fire for limp displays and propensity to commit costly mistakes.GOAL!!!Newcastle 1-0 Chelsea What a finish! Isaac Hayden gets a slight touch on Saint-Maximin's cross in the final minute to win it for Newcastle!What a finish ♥️😍🔥Heartbreak for Chelsea 💔#NEWCHEpic.twitter.com/OxZ0HTz1dp— SportCentre (@Livestream_102) January 19, 2020He added another gaffe to his ever-growing list by letting Isaac Hayden pillage all three points at the death for Newcastle. Arrizabalaga was hardly tested all evening, but when he actually was, came a cropper. He got a hand to Hayden's nudge, but his effort was so futile that the ball found the back of the net regardless. Another moment of indecisiveness meant the ex-Bilbao shotstopper had plumbed new depths.#6 Vicente Guaita (Crystal Palace) vs. Sheffield United | Feb. 2, 2020Guaita was poor in his handling of this cornerSheffield United must have surely felt a sense of redemption. After Henderson's costly mistake cost them the Liverpool tie, they were at the receiving end of a gift in the match to Crystal Palace as Guaita's mistake was enough to secure victory at the Selhurst Park.Roy Hodgson says Vicente Guaita has nothing to apologise for after his error that led to the winner. #CPFC "It's thanks to (him) we are where we are. Without (him) we'd have a damn sight less points. (He) owes us nothing, we owe (him) an enormous debt."#CRYSHU— Matt Woosnam (@MattWoosie) February 1, 2020Oliver Norwood played in a corner that went straight at Guaita, but he mishandled the ball to drop it behind his own line and award the Eagles a precious lead early on in the second half which they never ceded. The hosts were already frustrated by some resolute defending from the Blades but the Spaniard's clumsiness was the final nail in the coffin.