< “He won’t ever even know if you don’t say anything, anyway,”
“Oh, great. So you want me to lie to him now, is that it?”
In the grand scheme of things, sure, it's a tiny little white lie – hell, it shouldn't even be an issue, because what normal family gets this worked up over someone going to the library to study? - but it's still Lying To Dad. More pertinently, it's Playing Piggy-In-The-Middle again, being tugged in both directions at once and having to weigh up loyalties against each other. Which he shouldn't be having to do, right? They shouldn't be making him choose one or the other, his father or his kid brother. They're supposed to be one cohesive unit. That's what family is, after all.
And maybe he never actually expected the plea to work, because it was lame and Sam's got a point, he's old enough and ugly enough to look after himself (well, when it's something simple like this at least; walking to the library is one thing, their sphere of things another). But still. It's another thing that's worming its way under his skin about this whole affair, the fact that Sam's apparently stopped caring about doing things to give anyone other than himself an easy ride.
"Are you listening to yourself, Sam? Because... shit, man, you're being a dick."
Again, it's not exactly the greatest comeback ever, but whatever. Nothing about this situation - the way Sam's acting, the fact that he has to keep having this stupid fight, the stupid crummy motel room they're both stuck in - is anything other than lame anyway.