Marshall is definitely the goofiest of the How I Met Your Mother gang - and the sweetest, most of the time. He can easily get his feelings hurt by the others, as a result, but he bounces back every time (and occasionally gives as good as he gets). He's a gentle giant, and he's often the character surrogate for everyone who may love watching New York City, but find it a little intimidating, too.
Of course, Marshall is far from perfect. Like all of the characters on the show, he has his flaws, and they are often what make him funniest. Whether it's his awful fish-themed standup routine or the times that he and Ted have an actual fight (and not just a swordfight for fun), there are some dark sides to Mr. Eriksen, too.
Best: Always There For His Friends
One of the most appealing things about the show is how the core gang are always, always there for each other. No matter what, and at the drop of a hat. Marshall is no exception, and repeatedly shows that he is an incredible friend. He's the one who introduced Robin to the Hoosier Hut when she was feeling homesick, because he understood. He's the one ready with a pad full of legal questions to help with any quandary. And he's the one who picks Ted up after every single breakup.
Worst: Childish
At times, it is endearing to see Marshall's childlike joy and wonder in things. At other times, though, it can just be abrasive. He sometimes doesn't seem to understand what is appropriate behavior or conversation for a group of adults, and having him constantly joking around can actually be pretty jarring to watch, let alone to spend time around.
Best: Intelligence
Despite his childishness and occasional naivete, Marshall is possibly the smartest of the How I Met Your Mother gang. When the show starts, he is still finishing law school, but by the time it ends, he is an incredible environmental lawyer, and in flash-forwards, is shown to eventually become a judge! This is no small thing, and when the situation calls for it, he is quick to show off just how smart he is - without being arrogant about it.
Worst: Irresponsible
Despite Marshall's intelligence, he can also be incredibly irresponsible. He blows off studying and writing papers while in law school in order to chase down gifts (nice, but irresponsible) or throw big parties. He forgets his login to check his results after the bar exam.
Even after he is working for GNB, he and Barney blow off work to concoct elaborate pranks, and of course, no one can forget Beercules - or the fact that he is at the bar basically every night.
Best: Fun-Loving
The flip side of Marshall's irresponsible side is that he is always ready to have fun - and that he loves to seek fun out, without worrying or stressing about how he looks as a result. While other people might be too concerned with looking 'cool' to really let loose, Marshall is always there - boogie boarding in the rain, wearing a Dr. Suess hat, playing in an all-lawyer funk band, trying stand up (even if he's terrible at it), going on roadtrips, going to concerts... he is always up for something fun.
Worst: Pushover
Despite his size, and his intelligence, it seems pretty easy to get Marshall to do whatever you want. His friends routinely pressure him into doing things, and he says yes basically just to keep the peace. It's pretty clear that Ted has spent a big chunk of their relationship as a third wheel, but Marshall is fine with it. When Robin lies about being from Minnesota at his favorite bar, it takes an incredible amount before he says something. When Lily leaves him to go to San Francisco, he refuses to even consider that it was a selfish move, for months. Yup, Marshall is a pushover.
Best: Devoted (To Lily... AND Ted)
Anyone would be lucky to have a friend as devoted as Marshall. He and Ted met on the first day of college, and they are best friends until old age. He and Lily met not long after, and they end up married.
Once Marshall makes a commitment to someone, or something, he will always follow it through, and that's incredible. He's also a devoted son, if not always a perfect one, and is one of the only characters who routinely visits his family.
Worst: Too Focused On Tradition
Marshall can definitely be a stick in the mud, and he's not always the most flexible. When he's with his parents, he even turns back into a teenage version of himself, which is rarely a good look. He expects that Lily will follow his traditions, too, living in the suburbs - even though she is a city girl through and through. He clings to his traditions with friends and with Lily, and while this can be sweet at times, it can also be a little unnecessary.
Best: Wholesome
If there was one word to describe Marshall, it would be wholesome. He's just plain nice - he's the kind of guy who would get to know his neighbors, and help little old ladies cross the street. He's friendly, and he passionately cares about making the world a better place - he literally devotes his entire career to it. He's kind, he's devoted, he's friendly, he's positive, he's optimistic - he's clearly the most wholesome person in New York City, at least in this version of it!
Worst: Violent
Unfortunately, Marshall clearly has a bit of a violent streak - and while it's played up as a joke in the show, it's something that has long had fans raising their eyebrows. After the barfight, it quickly becomes clear that while Barney and Ted are completely inexperienced with fighting, Marshall is an absolute machine, capable of knocking out Doug himself. He has violent fights with his brothers, he takes great glee in slapping Barney repeatedly, and that's just the start of it.