Given their backstories you wouldn't think that these two would get along. Ted Kord started off as a mix of the standard silver age hero. He took the mantle of his idol, earned his place in the Blue Beetle legacy by training hard and making devices to help his mission. He was rich, but directionless and had trouble seeing the bigger picture at times. He was too distracted growing up to notice that his family was the only humans living in a alien town. Didn't get why homeless people wanted to live on the streets instead of taking the charity of others. When it came to his love life Ted didn't push his love interests often leaving him alone in the process. (I'm working under the assumption that Tracy, his stable loving girlfriend before DC was retconned.) He's the man that after his company fell to pieces under his fathers' run and his girlfriend almost ran off with another man (but backed out after learning he was married) shrugged it off to run off to the league.
Michael Jon Carter was dirt poor thanks to his dads' gambling loses. Given Michelle and Jons' refeneces to his mother being manipulated/fooled by Mr. Carter we have to wonder if his mothers' side did come from money. Nevertheless Booster is a jock that wants to make it big. While his greed is a big factor so is his concern for the well being of his family. A lot of fans assume that he was horrible at school but he put himself back in college, he made the effort. We never get too clear of a picture of his love life other than statements of him being something of a ladies man. Did he push Trixie away to spare her feelings? He already had a faked affair to promote himself, so how much is an image?
While Ted is older he wasn't always maturer and in some respects Booster understood things that Ted didn't get. When confronted with a 'vampire' it's Booster that pieces together that the lab that hired them has murdered/tested the other creatures and rationalizes that drinking blood isn't actually worse than them eating meat. Throughout the encounter Ted frequently complains that he needs money from this job to get material things while Booster is the one that actually pauses to consider their actions. What's more telling about their point of views is where they differ after they find the body of the creature once it flees in fear. Ted assumes that the vampire slipped and fell in it's panic. Booster has a darker more realistic idea that it was suicide to escape them noting that it had made the area it's home and had to know the lay out.
We get to see into both of their heads on how they view their situations and each other. In Countdown to Infinite Crisis Ted notes how poorly their seen by their peers. Though he's harder on himself and more awed by the other heroes than in the past Ted knows that the two of them are more than what people see. How he sees Booster is interesting as he notes that Booster isn't a thief which he pointed out that Booster was indeed one when he learned of his friends' origin. It's an outright dismissal of a fault but the point behind it is that Ted doesn't see Booster as a bad person and knows that he wants more than to be known as a sell out hero. He gets that when no one else does.
At his home Ted goes on to elaborate about the rumors about Booster knowing the future. Well he did tell Ted about this in the past although not all his information is accurate due to how long ago the events were. But Beetle sees what the other heroes failed to get, that Boosters' friends are the most important thing to him. From Michael taking the lightening bolt to the chest for his buddy and Booster freaking out about everyone he cares about dying (all of which have returned I believe. Sue counts since she came back as a ghost.)