Conversation so far:
What was Sinatra's first debut?
Las Vegas Nights.
What was his first musical film?
Anchors Aweigh.
What was another of Sinatra's musical films?
Till the Clouds Roll By.
Why did Sinatra's career slump?
he was rarely enthusiastic towards his own acting.

Question: Were there other reasons for his career slump?
Self-contained rewrite: Were there other reasons for Frank Sinatra's career slump other than pessimist toward acting??