Farhampton - S8-E1
Character mistake: When Barney is telling his story to Quinn in a minute he says, "Ted and I stopped being friends, Ted got hit by a bus, we made up." Barney got hit by a bus, Ted got hit by another car. (00:12:10)
Character mistake: Marshall's whole career focus is saving the environment, so it's a poorly written character choice that he buys plastic glasses to avoid a dish-washing feud, boasting that they can just throw them away. (00:20:10)
Dowisetrepla - S3-E7
Character mistake: In the scene where Robin and Lily are talking in the kitchen, Robin makes a reference to Mount Waddington being the tallest mountain in Canada. The tallest mountain in Canada is actually Mount Logan.
Character mistake: When they see Robin on the news at the end she says "Metro 1 News" instead of "Metro News 1". (00:12:20)
Character mistake: In another episode it is revealed that Robin hates nicknames and reacts badly when she, or anyone else, is given a nickname. However, in this episode her and Marshall give each other nicknames, and she doesn't seem bothered at all.
The Chain Of Screaming - S3-E15
Character mistake: Marshall, especially as a lawyer, should have known that simply screaming "I QUIT" towards his boss wasn't official resigning. He would have to write a notice letter with his signature in order for his resignation to become official.
Suggested correction: Alot of stuff can be recycled. He would simply recycle the used plastic.
Ssiscool ★
You can recycle the plastic but you have to wash it first, defeating all the purpose of buying it in the first place.