I do find it understandable if anyone finds Messi boring due to the sheer efficiency of his game.
Sport, and football specifically are best when there is unpredictability, suspense, drama. We're not just watching to appreciate the ability on show, we demand entertainment, theatre, spectacle.
Someone like Neymar goes out of his way to produce the audacious, the flamboyant. The rainbow flick the other day, the flick, turn, and volley a few months ago. It's an important part of what makes football so much better than any other sport.
If you were showing a footballing novice a player to try and get them into the game, you'd go for a Zidane, a Ronaldinho, a Neymar, for sure.
Messi does still have moments of flair, and moments where he goes out of his way to entertain, but he's not one of the all time performers.