Maybe it's because he grew up a child of privilege. His family has oil money, so maybe there was always a way to buy his way out of things.
Or maybe as a high-school football superstar in small town Texas, he got used to getting away with anything.
Who knows why, but clearly, Manziel believes rules are for someone else.
Look at what happened earlier this summer at the Manning Passing Academy. Manziel was invited to be a counselor/coach at the prestigious camp run by the first family of football. Only the best of the best college quarterbacks are asked to participate.
But Manziel was sent home early.
Manziel has disputed reports that he was asked to leave, but Sports Illustrated's NFL guru Peter King, one of the most respected voices in sports media, has reported that Manziel was told it would be best if he went home.
With no explanation, Manziel was late for one coaching session on Friday, then completely no-showed a session on Saturday morning.
Some have said he was hung over, another charge that Manziel disputed, saying that he overslept and couldn't be reached by camp officials because his cellphone died.
But the bottom line is, he didn't leave the Mannings with a great impression. And in case you're wondering, Archie and his sons carry some pretty serious cachet in NFL circles. You suppose Peyton will have many positive things to say if a team calls him about Manziel before the draft? What do you think Eli will say if a team asks whether it should pick Manziel in the first round and make him the face of the franchise?
If you're a young quarterback who hopes to play in the NFL one day, you should probably be on your best behavior when you're around the Mannings.
Another rule that Manziel chose to ignore.
Who knows where all of this is going to lead. My hope is that all of these NCAA allegations are untrue, that Manziel is cleared of any wrongdoing, that he plays every game for the Aggies this season.
College football, after all, is more exciting with Manziel on the field.
But perhaps the only way he's going to realize that the rules do apply to him is if he's held accountable for breaking them.
That may be the only way he'll learn.
Jenni Carlson: Jenni can be reached at (405) 475-4125. Like her at facebook.com/JenniCarlsonOK, follow her at twitter.com/jennicarlson_ok or view her personality page at newsok.com/jennicarlson.