A few weeks ago, I was chatting with a friend and DM and she mentioned that one of the people we play with will "Never fail a roll if she really wants to succeed". We played a game last night and I paid attention and noticed this for the first time - she failed maybe one roll, at the beginning of the game, and the rest of her rolls were all in the 20s. I think she had four or five nat 20s during the game, which was only about 2 hours long.
I just don't get it. Why cheat? Doesn't it take all the fun out of the game? We joke that the character I'm playing is cursed because he rolls so low so frequently on all the things he's supposed to be good at, and it CAN be frustrating, but I've still never felt tempted to lie and cheat about a roll. What's the thinking behind this, and how do you even bring it up with someone?