Watched The 39 Steps last night. Absolutely delighted that in 1935, Hitchcock thought through what a modern audience would be waiting for and gave us a character announcing "we've a room, but there's only one bed".
(Same thing in North by Northwest as well. Man knew what clichés he liked.)
Second favourite bit is the point where our protagonist has to improvise a political speech without knowing precisely a) who he is meant to be or b) whether the meeting was for the Liberals or the Conservatives https://youtu.be/aalwXQINtio