Enthusiasm was ill-bred. Enthusiasm was ungentlemanly.

It was Winks who summed up the general impression and put it into a form they all felt was conclusively damning
...

'He's very enthusiastic,' said Winks.

Enthusiasm was ill-bred. Enthusiasm was ungentlemanly. They thought of the Salvation Army wit its braying trumpets and its drums. Enthusiasm meant change. They had goose-flesh when they thought of all the pleasant old habits which stood in imminent danger. They hardly dared to look forward to the future at all.

W. Somerset Maugham, Of human bondage (1925), 65