Dobie became the latest Warrior to reach a century of appearances for the club, with his team-mates marking the milestone following Glasgow's hard-fought encounter with Munster.
Speaking to the squad after the match, Horne highlighted the journey taken by Dobie since arriving at Scotstoun straight from school as an 18-year-old.
"To play 100 games at this level of rugby is a special achievement, but to do it for the Glasgow Warriors, first of all mate, you should be so bloody proud," said Horne.
"Coming in as an 18-year-old, you know, that couldn't have been easy. Straight out of school, massive hype around you, expecting the world, and you just put your head down and you just got on with things.
"Your attitude is unbelievable. Nothing seems to waver, nothing seems to sway you. You just seem so unflappable all the time, and it's something that I could learn a thing or two from."
Horne also paid tribute to the versatility Dobie has displayed throughout his Glasgow career, having featured at wing in addition to his customary role at scrum-half.
"You're one of the few guys in the world that can do everything," said Horne.
"You can get up in defence and smack boys, you can skin people on the edge with your pace and feet, you can win high balls. You've got genuinely every skill under the sun.
"But the one that stands out for me the most is your toughness.
"Regardless of where you play, what position, you're the guy getting up, making huge tackles, getting your body, head on the line.
"In the air, you're flying up, bashing boys, just putting your body on the line, and it's so inspiring for us older guys and for everyone at the club.
"We should take a leaf out of your book because it's the one trait that you can't teach, and you've got it in spades.
"We're all so lucky to have you as a team-mate, and we're so proud of you reaching 100 caps for Glasgow Warriors."
Dobie admitted the circumstances surrounding his landmark appearance were close to exactly how he would have imagined reaching the milestone.
"Honestly, if I was to draw up how my 100th cap would have looked, it would have been pretty close to that," he said.
"We had to fight right till the end, and thank you very much to everyone that was out there, putting it right in till the end."
The 25-year-old also thanked the Warriors coaching group for helping create an environment in which he and his team-mates have been able to develop.
"Thank you guys for pushing us all, for creating an environment where we can grow and be the best versions of ourselves on the pitch and off it," said Dobie.
Turning to his team-mates, Dobie reflected on his arrival at Scotstoun as a teenager and the players who helped him settle into professional rugby.
"To be honest, as George said, I arrived at this club literally fresh with my school bag, 18 years old," he said.
"To you boys, thank you very much for everything.
"Honestly, it's inspiring to me, and I thank you guys for always being there for me.
"We've had some good times on the pitch and some good times off it, so I really appreciate all of that."
Dobie finished by dedicating the milestone to his parents, thanking them for the sacrifices that allowed him to pursue a career in professional rugby.
"Lastly, to Mum and Dad, thank you for being here today. I really appreciate it.
"I know you guys support me from afar, or whenever you can make games, both for Glasgow and Scotland. I really appreciate everything that you've done for me.
"There's no doubt that I wouldn't have played for this club once, let alone 100 times, if it wasn't for how you guys brought us all up and all the sacrifices that you made for all of us.
"So I'd like to dedicate these 100 caps to both of you. Thank you very much."