Some characters it just seems like they do the same thing over and over. Of course the more experienced players know how to utilize all their characters tools.
Some characters on here i dont personally agree with but i just try to put as many people on as i can that i've heard complaints about.
My choice: Jak. 9/10 of them i've fought just rifleshotrifleshotrifleshot and if you get close to em they punch you a few times until your a good distance away, then start back up with the rifle. I have found ways to overcome this but its still pretty annoying.