Goofus is the kid on voice chat screaming at them all that they suck and that they're noobs who need to die and get out of his way. Gallant is understanding when someone has a panic attack, and helps in any way he can.
Goofus considers panic attacks an excellent opportunity to go through someone's stuff and eat any Doritos they might have been saving. Gallant always puts error bars on his graphs.
Goofus is a strong, loud supporter of correlation = causation Gallant asks the owner before petting dogs out for walkies in his neighborhood.
Goofus deliberately pets dogs with service dog vests on. Gallant helps his friends shop for new clothes, and is polite when he thinks something doesn't suit them.
Goofus picks out the least flattering clothing possible, and says it looks great. Anything good he calls super ugly. Gallant always checks the links on pointless call out posts.
Goofus makes callout posts. Without links. Or evidence. He just enjoys seeing the wreckage created by those who blindly believe. Gallant doesn't criticize the weird things his friends collect.
Goofus takes pictures and posts it on the internet with "lol look at this freak" attached. Gallant understands the risks of sharing eye makeup and makes sure to have eyeliner/mascara that is specifically his only.
Goofus assumes all collections are intended for use as dildos, and kinkshames them. Edit: ninja'd. Goofus goes around mixing bits of his makeup into other people's makeup so they can be Mascara Brothers. (Like blood brothers, but mascara.) Gallant tags his NSFW posts.
Goofus tags his NSFW posts...with anything and everything but NSFW. Gallant keeps his posts to the appropriate tags.
Goofus spams every tag. With everything. Gallant doesn't mock new fans of things for not knowing everything about a series.
Goofus declares anyone who doesn't know everything ever about a thing they like a 'fake fan'. Gallant respects people's boundaries.
Goofus tells random strangers the gory details of his genital piercings. Gallant uses blacklist extensions to avoid his squicks and triggers.
Goofus intentionally goes in tags to complain about being triggered. Gallant doesn't block anyone who disagrees with him.
Goofus blocks everyone who isn't in complete and total agreement with him about everything ever. Gallant offers you tea when he's making some for himself.
Goofus pours tea down your throat while you're unconscious. Gallant leaves positive comments on fanworks.
Goofus leaves ship hate on stories he hasn't bothered to read. Gallant pays for the groceries of the person in front of him in line when their card is declined.
Goofus deliberately uses an expired or otherwise invalid card at the grocery store, then tries to wheedle or intimidate the person behind him into paying for his groceries. Gallant, when making tea, asks if anyone else in the house wants tea and makes sure to heat up enough water for everyone.
Goofus asks if you want tea, but if you say yes, he'll proceed to come over to your house every day after with a cup of tea that he forces you to drink. Gallant cleans up after he makes dinner.
Goofus decorates the room with the leftovers after he makes dinner. Gallant cleans his cat's litterbox regularly.