Is "tooting your own horn" a desirable trait?

I have a friend, let’s call her Cheryl, who is always going on and on about her wonderful talents and personality. I am finding it increasingly hard to tolerate Cheryl and may have to end the friendship. In my mind, it is for others to see what you do well and tell you – if they want to – rather than for you to be bragging constantly about your accomplishments. Your thoughts?