i'm in your conscience
I immediately thought of that Haunter when I saw this thread, haha. So yes, my vote is going right to that one. Another annoying one is in RS (I think it was changed in Emerald though?) when you trade Bellossom for Corsola. Corsola can be fished for and aren't that uncommon whereas Bellossom is a better Pokemon and there's only one easy to obtain Sun Stone. And if you're playing Sapphire, then you don't get to steal them from wild Solrock. So that especially makes it bad.