Something that I constantly need to remind myself: sometimes... sometimes I'm wrong. You would think that I wouldn't need to make an effort at this - after all, it happens often enough (and believe me, there's always someone nearby to point it out).
That being said, though, one of my inherent flaws is an unsubstantiated belief that I know better than most people. Fortunately, though, I've been working in the health and fitness industry long enough to realize that what's right today, is often wrong tomorrow - and vice versa. Furthermore, I've seen methods and approaches that have worked for 5 other people not work for 2, and I've seen people doing something that we swear is going to hurt them having no effect on them at all. And it's because of this that I've become that much more inquisitive, and open-minded - just because something worked before doesn't mean it's going to work this time, so I'd better be ready with 3, 4, 5 other approaches unless I'm ready to admit quick defeat (another thing I do very poorly).
It's a fine line - we all know that the definition of insanity is doing the same thing over and over and expecting different results. However, there are times where we need to step back - if someone brings an idea to the table that's been tried, we need to consider whether or not the reason it didn't work before is because the idea was bad - or because we ourselves executed it poorly.
Sadly, I haven't figured out a personal "litmus test" to measure this - sometimes it's intuition, sometimes its the conviction of the person presenting it... and sometimes I need to just step back and watch to see what happens. And while this can be frustrating at times, at others it can be educational or, once in a while - even inspirational. I've been told my realism can, at times, border on pessimism - but I'm working on it. And the more often it happens, the more I can learn.
So take what I say, be sure that you're not simply making the exact same mistake that I made...
Then prove me wrong.