Across nine seasons there is no doubt that fans found themselves adoring Barney Stinson, a character with a plethora of insecurities, issues, and flaws, getting more invested in his story than arguably anyone else's. It is for this reason fans have found it easier to forgive a lot of the terrible things Barney has done over his life, far easier than other How I Met Your Mother characters.
However, despite the forgiving nature of fans, Barney does a lot of things that many audiences have found unforgivable. Whether it be doing something to a specific woman, or to women in general, Barney does a lot of stuff fans still haven't let go of.
Gym 'Investments'
At one point in How I Met Your Mother, the gang decides to get in shape and attend a gym. This leads to the reveal of one of Barney's sicker long-term projects.
As he tells Ted, he has 'investments' in the gym, these basically being women who Barney deems as having a larger than ideal body, and them and be there for him in their weight loss journey. Barney believes that once they've lost the weight, then they are worthy of sleeping with him, which is gross..
Manipulative Proposal
The Barney/Robin relationship is largely viewed as at least better than Robin and Ted, but the proposal is still a highly divisive aspect of their relationship.
Barney's proposal to Robin consisted of a lot of lies, emotional and mental manipulation, and a convoluted plan that left Robin severely hurt for a long time. For this, many fans have not forgiven Barney, especially since the two did not even last.
Attempts To Feel Up His Best Friend's Wife
Barney made a lot of es at Lily over the years, constantly referencing wanting to have sex with her, as well as his infatuation with her body, something Marshall and Lily treat as funny and minor even though it isn't.
The worst instance of this all, though, was when Barney conditioned Marshall to want Japanese restaurant Shinjitsu every time he sneezed. Barney laid out a plan to master their elaborate food preparation and use it in a bet to either see or touch Lily's breasts, which at the time were naturally larger due to her being pregnant.
Ditching A Woman In The Woods
The episode '"The Bracket" provides many, many insights into the disgusting ways Barney has treated women, most of which are never explored and just teased, like the fake baby.
One that did get given more context was Barney abandoning a woman in the woods. Holly was the victim of this, with Barney stealing her truck and abandoning her in the bear-infested woods. He very well could have sentenced that woman to death.
Filming Everyone Without Their Consent
With his job making him "sixteen craploads a year", Barney Stinson has a lot of disposable income which he often used on tech for his bachelor pad, as well as other creepy gadgets.
One thing he invested in was multiple hidden cameras. Not only did he keep these in his bedroom and film women without their consent, but he also kept cameras in his friend's houses too, which was yet another questionable aspect of his proposal to Robin.
His Lesbian Play & Jokes
One thing a lot of older shows struggle with is their unacceptable homophobic and transphobic jokes and comments, and How I Met Your Mother made more than a couple.
Arguably the worst thing the show does in of being offensive to the LGBTQ+ community is when Barney sets out to hook up with a lesbian, doing so by wearing what he thinks a lesbian would wear. Barney, alongside Ted, often fetishize lesbians, which is problematic.
His Fat-Shaming Of Women
It is not just the LGBTQ+ community that is the butt of many Ted and Barney, and even occasionally Marshall's jokes. It's also those who are have a larger body than he deems ideal.
So often throughout the show, he comments about how undesirable they are, and how he has no interest in sleeping with them, body shaming them alongside women who are over the age of thirty. This all being despite the fact that Barney spends a big chunk of the show over the age of thirty, and himself has gone through a phase of gaining weight.
Sexual Assault
How I Met Your Mother is told from a massively unreliable narrator in Ted, so everything that Barney in particular does should be taken with a grain of salt.
However, there are times that Barney does not only exhibit behavior bordering on sexual assault but actually commits it. The story he tells Nora, the comment about slapping a secretary, the whole 'always getting the yes' narrative, and a lot of his tricking often drunk girls into bed is all unacceptable behavior.
Sold A Woman
Of all the things Barney does that fans have failed to forgive over the years, the one that fans hope is an exaggeration by Ted but never actually happened is his selling of a woman.
Fans do not get a lot of context on this instance, but when he is apologizing to a woman he thinks he slept with and forgot, he mentions how one of the worst things he has ever done was sell a woman, exchanging her for a Mercedes. There are a lot of questions, as well as shock raised from this comment, and it is perhaps the most unforgivable thing he does if he truly did do it.