Its not about whether they are your friend or not. Blue technically was your friend...he just was an asshole.
My main issue with recent rivals is that I felt like I was crushing their dreams. Especially gen 6's rivals. Serena/Calum were children of some hot shot trainers, knew their shit and all that...and yet some kid who just arrived stomped all over them with ease, got the mega bracelet, save the world and everyone loves them. Like goddam man.
Cheren and Bianca weren't difficult but each at least found their place within the world (although I wish Cheren was more of a challenge since he seemed like he was trying to keep up). Barry (which I learned in retrospect) , again not a challenge, was atleast always a step ahead of you and for me (and partially due to my rule of not reusing pokemon I used before) he occasionally was tough to beat...he even has a mini arc of learning that he has to actually take things a bit more serious after getting styled on by Team Galactic peeps.
I get that, since I am a series vet by this point, it never will be "OMG SUPER DIFFICULT" thats not really what the series is about afterall...but at least put on airs that this person is worth my time. Gen 6 made me feel like a bully lol. At least Wally was supposed to be someone weaker than me...