I found this offensive. It must look stupid for me to be offended at something that harmless, but it shows a fundamental lack of understanding of Chinese culture. And that so happens to have set me off today, I guess.
It's in poor taste to "strut your stuff" directly by describing how good you are.
We tell people we're good at something by BEING good at it, not by telling them.
If we're good at something, it's because our teacher or parents did a good job of teaching us. Based on that, showing off means praising our teachers.
We call attention to our positive traits by reflecting on how they can be improved and seeking advice on such. Attitude and aptitude go hand in hand. Those traits that we care most about are most likely our strongest ones.