Ok so I was struggling incredibly hard to catch Mewtwo in FireRed. Then I said to my friend ThatDudeWithALife "if you catch Mewtwo, I will stop shipping you with your friend." AND HOLY CRAP. AFTER 10 REGULAR POKEBALLS HE CAUGHT IT! HERE'S THE SCREENSHOTS I COULD TAKE:
(I started with 90 pokeballs btw) And you can see that Mewtwo was caught with a pokeball.)
this means that Mewtwo hates me but loves ThatDudeWithALife