Definition of "stimulating"

Jeeves: Foreign travel often liberates emotions best kept in check, sir. The air of North America is notoriously stimulating in this regard, as witness the regrettable behavior of its inhabitants in 1776.B. Wooster: Hm? What happened in 1776, Jeeves?Jeeves: I prefer not to dwell on it, if it's convenient to you, sir.

1991 May 12, “Kidnapped!”, in Jeeves and Wooster, Series 2, Episode 5