The first time we are introduced to Lucas, Maya notices him and enacts the troupes of a romantic relationship. Then she pushes Riley toward him.
It is only after all this that we even learn his name.
In the pilot episode, Lucas is involved in several scenes.
He walks in right when Cory says, "Bad things happen when you don't know who you are."
He doesn't follow Riley or Maya when Maya acts up, and he asks Riley why she didn't stop Maya.
We learn later in Girl Meets Secret of Life that Lucas was involved in a fight that got him expelled. He goes to New York, reluctant but willing to start a clean slate.
He repeatedly states not to judge something by how it appears, but he puts on a front, why?
As I focused on his character throughout the narrative, I couldn't help noticing that Lucas is very aware of the dynamics of the "square dance".
He has a "game" with Maya that he throughly enjoys, acting out the stereotype of the cowboy and the gentleman.
And in Girl Meets First Date, he has a very interesting conversation with Farkle.
In Girl Meets Texas, Lucas has to face a serious fear and move past regret. Riley and Maya sign him up to ride Tombstone the bull. Lucas's reaction to this is very obvious:
During their time in Texas, the dynamic between Lucas and Maya changes, and we learn that Lucas has been afraid of Riley and Maya since he met them.
Right after the campfire scene, Lucas has a very interesting conversation with a sheep and a bull. He tells them that he was afraid of both of them. The symbolism here is obvious.
Riley is the sheep. Maya is the bull.
Lucas regrets his failure with the sheep, but he his determined to make the record with the bull.
He comes to terms with his past here, but not his heart.
Then in Girl Meets Jexica, we learn his favorite song is Desperado: a song about a guy afraid to fall in love who doesn't make decisions.
This is a big clue that relates to the "face" he puts on. Based on his past experience, Lucas doesn't want to mess up again. He's been there, done that, and he doesn't want to repeat the same mistakes.
While Riley, Maya and Farkle change who they are, Lucas doesn't. Twice.
In commomism, he doesn't follow them down the think-alike train, and in yearbook, Lucas is very clear about who he is, and he lets everyone know that despite what everyone thinks about him, he is not okay with his friends losing who they are.
Let's not forget in Girl Meets Squirells, he never answers Eric's question about Maya teasing him.
"Well, why do you let her?"
We know that Lucas has a different side than the "face" he puts on with Riley. Maya accepts that side. Riley doesn't. Farkle calls it "Texas Lucas".
In Girl Meets Triangle, Lucas finally makes a decision, and it's obvious who he chose.
His reaction to Maya as Riley in Yearbook foreshadows his reaction to Maya in True Maya when she says that she doesn't know who she is anymore. He reacts very strongly to Maya's behavior, and he tells Maya that he's "been down that road before" right after Maya says she wants to do something bad.
So why did the triangle (not triangle) take so long to reach a conclusion? Because Lucas is afraid to fall in love, take the risk. But the one he's really afraid of isn't Riley, it's Maya.
But Maya continues to push him towards Riley, and he goes along with it. Even when he has to let Maya go.
Even when Lucas and Riley have their moment, he tells Riley that Maya pushed him toward her. So now he's going along with what would make Maya happy. Poor guy.