tom is not just a friend of the family—he's the son of mrs. gardiner's cousin, and she tells mary early on that tom has been kindhearted since childhood

not only that, but tom has... you guessed it... four sisters, and is the younger son, hence him being a working man

tom is way more teasing and flamboyant in the book, which makes his lack of self-confidence when it comes to matters of the heart even more interesting

tom wanted to be a poet but realized early on he had no talent for it. he became a barrister instead because, he says, there were clear answers to seemingly everything (character building !! but as a lawyer myself i'm like um 90% of the law is "it depends")

since he can't be a poet, he is a published poetry critic instead. and he defends wordsworth's writing so fiercely that his friends make fun of him for it

in fact, after tom leaves and mr. ryder is courting mary in earnest, they talk about poetry reviews. mary mentions that tom dislikes one of them, and will responds, "that's because its reviewers have not always been kind to his adored wordsworth. you know how loyal he is, once he has found something to love." (help i've been stabbed)

mary doesn't just read poetry at tom's recommendation: they have a challenge where they each must read the other's choice. for tom, mary chooses a volume and a half of catharine macaulay's history of england. for mary, tom chooses wordsworth's lyrical ballads

mrs. gardiner is scared that tom will hate reading it and be bored to death when talking to mary about it. instead, when the two meet in the drawing room to discuss their reading, she keeps checking on mary and tom only to find that they discuss it for hours

before she even knows that it's his favorite, mary tells tom that "tintern abbey" is her favorite wordsworth poem

tom doesn't just do a poetry recitation. early one morning, he takes her and mr. gardiner to westminster bridge in a carriage to replicate wordsworth's vision in "composed upon westminster bridge" (rather than in a garden)

as mary is falling in love with tom, she takes up playing piano again

a scene that isn't included in the show is when tom goes with mary and the gardiners to visit vauxhall gardens. he and mary play a game while walking around in which they make up stories for the strangers they pass by. tom gives one man a jobless fortune-hunter background and says he lives at the "wrong end" of brook street. coincidentally, we meet will ryder moments later... and he reveals he doesn't have a career and lives on brook street...

mr. ryder visits the gardiner home multiple times to talk to mary. he tells mary that tom "has an excellent opinion of [her]—he always speaks of [her] in the highest possible terms—and there is no-one whose perceptions [will] trust[s] more." so part of the reason mr. ryder initially becomes so interested in mary is how tom talks about her <33

at the dinner party mr. ryder hosts, mary takes some sprigs of lavender out of a bowl. tom leans over and asks to have one for himself. when she gives it to him, he wears it in his buttonhole for the rest of the evening

at the same party, mary, tom, and mrs. gardiner discuss jam (lol). mary insists she won't eat anything weirder than raspberry or strawberry jam. tom responds, "so even if we were married, i could not obtain the wish of my heart—greengage jam at breakfast." (!!!!!)

when mr. hurst is drunkenly yelling to his wife about mary being "perfectly tolerable" when the party breaks up, tom gets super mad and apologizes for not running down the stairs and telling him to shut up

since the character of ann baxter doesn't exist, nearly the entire time tom knows mary, he's secretly building up the courage and money to propose, with no other impediments… only to be thwarted by will at the lakes

when they're at the lakes, tom gives mary a sprig of honeysuckle before mr. ryder even arrives. and when will gives her the primrose on the hike, the petals are actually a little crushed. mary turns to tom and says she saved his flower in a vase, but he's too preoccupied with jealousy to hear her

when tom leaves, he leaves a letter for mrs. gardiner, and the last line, all by itself, says: "i beg to be remembered to miss bennet"

when tom disappears, he specifically goes walking around tintern abbey to wallow

after tom proposes, there's a reference to emma: "i might add in my own defence that if i had loved you less, i might have ventured more. it was hard to be bold when i was only too aware of what i stood to lose."

lucas being in 4k makes sense