The secret is: they're all dangerous!
The great (really great) Garry Kasparov just lost in 7 moves:
From Leonard Barden in the Guardian:
[Event "Zagreb blitz "] [Site "?"] [Date "2021.07.??"] [Round "?"] [White "Shak Mamedyarov"] [Black "Garry Kasparov"] [Result "1-0"] [ECO "D20"] [Annotator "Regis,David"] [PlyCount "13"] [SourceVersionDate "2021.07.16"] 1. d4 d5 2. c4 dxc4 3. e3 e5 4. Nf3 exd4 5. Bxc4 Nf6 (5... Bb4+ $1) 6. Qb3 Qe7 7. O-O (7. O-O d3 (7... Nc6 8. exd4 {threat Re1}) 8. Ng5 h6 9. Bxf7+ Kd8 10. Ne6+ Bxe6 11. Bxe6 Nbd7 12. Bxd7 Qxd7 13. Qxb7 Qd5 14. Qxd5+ Nxd5 15. Rd1) 1-0