what is the meaning of given someone a standing ovation

It means their performance was not just excellent, but so superior as to far outshine what could have been expected. You were so impressed that simply clapping is not enough show of your appreciation.

To me, a standing ovation should be spontaneous and enthusiastic. I get very annoyed when, after a performance, some people stand and clap, and others, looking around and seeing someone giving a standing ovation, also struggle to their feet to join in. If you were not so moved by the performance that you simply had to jump to your feet and applaud, stay the hell seated. A reluctant Standing O is just succumbing to peer pressure -- maybe it means you are not enough of an audience to appreciate good work.

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