Oliver: This will be good for her, having a role model. Someone better than me.Laurel: Oh, youre not so bad.
The one recurring theme that we see in the show is the idea of role models and what it means to be one. Oliver is shown to have been a negative role model both in his civilian identity and as the Hood. Thea became a wild party girl and drug user because thats how she remembered her brother prior to him being stranded on the Island, she wanted to be like him so badly. This admiration turns into bitterness and anger after his return due to how much his death hurt her. Its rather telling the above exchange Oliver has with Laurel. He sort of acknowledges he has not been a good example for his sister.
Olivers crusade as the Hood was a revenge-oriented crusade where he said,You have failed this city, to anyone on his Dads hit-list. He also wasnt above using lethal force in said crusade. The beginning of Season 2, we see several men have decided to imitate his example by donning similar costumes and calling themselves, the Hoods, and taking the MO of Oliver Queen to its logical extreme. Its as Diggle told him in the Season 2 premiere concerning the copycats, Theyre like you, Oliver, except without your level of restraint.
Fortunately, Oliver was a positive role model even at most homicidal. The reason Roy Harper commenced crime fighting is because Oliver saved his life as the Hood. He later went on to become a hero in his own right.
Thea eventually also follows in Oliver positive example too. In Season 2, she stops looking up to her brother after finding out he hid her parentage from her. She returned back to looking up to him,after finding out about his identity as the Arrow. She then goes on to becoming his sidekick after Roy left.
In Season 4, we see Oliver desiring to be a symbol of hope and inspiration to the city. Thats why he took up the name,Green Arrow, and ditched the old persona.
Fast forward to Season 8, The Anti-Monitor calls Oliver, The Paragon, saying he is one of the greatest heroes in the multiverse. His sacrifice during the Crisis and transformation into the Spectre afterwards becomes vital in the reconstruction in the multiverse after the Crisis on Infinite Earths. And the series finale, the news reporter said that Oliver inspired an entire generation of heroes.
Some people, are also seen as examples to Oliver Queen. Its clear that Oliver followed in his moms example in running for mayor.
This idea of what it means to be a role model also appears elsewhere. Joe Wilson states he saw his dad, Slade Wilson, kill a guy and that lead to him killing someone and it ultimately lead to him becoming a crime lord. Another notable example happens with Sara. We have Sin who looks up to Sara greatly. Another example would be Laurel who follows in her footsteps as the Canary after her death. Then after Laurel died, Dinah Drake and Black Siren replace her as the Black Canary and start a group called, the Canaries, of which Zoe Ramirez was a member.