Too lazy to pick a pic
Yeah, when you look to Ash's side, it's very ungrateful from the eon duo, since latias took her jolly time to know him and she learned he's reliable.I can't help thinking Latios/Latias were portrayed a bit ungrateful at the end.
As for Latios, I can somehow understand if it's still a bit suspicious of humans considering what it went through. You could argue, though, that after seeing what Ash and his friends had done in order to save them, Latios could have become a bit more open-minded, at least towards Ash.
The bigger problem however is Latias: It's been stalking our heroes since the very first episode of MPM. It has been rescued and healed by Ash several times. And after all that there was a short, unemotional farewell scene where Latias was somehow acting like "Yeah, that's it. I'm off. We had a nice time but we'll never meet again."
What I'd like to say is that send-off scene could have been done much better.
When you look to latios side, he was hurted by fleeing from the hunter all the time while latias was far and safe. On the top of all, latios was useless by himself and he needed the help of other human to actually have a chance to win.
From his POV, he probably felt both hurted and humiliated. It's bad because we know Ash’s core and we know that, when he wants to help, he actually means it. For latios, it was a desperate time.
Said that, I didn't like about something that bittersweet exactly by what is Ash's penultimate episode. But, eh, nothing to do about that, now.