(Description edited because my 14 / 15 year old self was really immature about the matter.)
Not to say that it's impossible.
I don't think it's right to pair an OC with a canon character if you cannot keep them in character.
Characters like say, Sasuke Uchiha would not give up his revenge for some Kunoichi that he knew from the leaf.
What's even more difficult to pull off is if the canon character is paired with someone else in canon already. It's just...well, rarely ever realistic? It's kind of hard to come up with an explanation about why the canon character is with your OC even though they're with, or married to someone else in canon. The only way I've seen that done right is through AUs or if the OC and Canon character break off their relationship sometime before the end game canon couple is a thing.
You wanna do AUs for fun? Go for it!
You wanna pair your OC with your favorite canon character? Have a blast with it!
But don't bend the canon or change the character to fit your OC. If you want it to work so badly change your OC to fit the canon.
OCs are supposed to be just for fun, but don't limit yourself by refusing to change them or the relationship that they have.
If you can pull it off, by all means please pull it off, set the bar for good OCxCanon.
If not, there's nothing wrong with OCxOC!
I'm willing to have an open discussion.