We all make mistakes. But some are more career limiting than others - and many of those are avoidable. Career coach Kathy Caprino says in a recent LinkedIn post that throughout her career, she made a number of huge mistakes. "I did some important things right too, but my missteps were legendary (at least in my own mind)," she writes. "When I look back on my 30 years of working, and the careers of the hundreds of folks I train, coach, and teach, five blunders stand out from all the rest as the most negative, damaging, and irreversible in your career and professional life." Here are three of them.