As I'm sure I've said before, being a parent brings up your own internal crap. Let's use a fictitious example: you were really afraid of the dark as a kid, and now your kid freaks out over some monster she supposedly sees in the middle of the night. If you had your own monster issues when you were a kid, then this is going to bring up some vicarious angst for you because you're having to watch your kid experience it and feel the associated emotions.
My "thing" is disappointment. I have to say that my daughter deals with disappointment a heckuva lot better than I do. I tend to get more disappointed over things than she does. It's good that she lets things roll off her like I wished I would. I worry that my internalization of disappointment will start to rub off on her. I have to keep it in check so it doesn't start to.
Obviously, something happened when I was a kid that really, really disappointed me. I can surmise what it was, but it also could have been a series of small things that became practically a mountain to me. My response to that was to try to avoid disappointment at all costs (because if you ignore something, it will go away...right?). For some reason, I've found that it's easier to avoid life's big disappointments than the smaller ones.
Life's Big Disappointment #1: Unrequited Love
My Stupid Solution That Avoids Disappointment: Don't love anyone first. A crush is okay, but keep it in perspective that you really don't know the person and are just basing it on superficial stuff. Pull away if you start feeling more than you think is being returned.
Life's Big Disappointment #2: Not Getting Your Dream Job or Not Getting Into Your Dream College
My Stupid Solution That Avoids Disappointment: Don't apply for your dream job. If you do apply, give yourself the most critical self-talk saying that you know you will never hear anything positive. If you get anywhere, it's a +. If not, you expected to be rejected anyway because you suck. Also, you never want anyone else how much it means to you, and even better is if no one else knows that you even applied.
If you put a wall up around yourself, I do think it's easier to stay away from the big disappointments. However, this really isn't a sound strategy because you become stuck in emotional paralysis.
Even if you do put up the wall, there are still going to be little disappointments in life. Like you were really excited about upcoming plans with a friend, and your friend cancels at the last minute. Your friend might have a totally legitimate reason (like getting hospitalized), but it still sucks. Or you get a B on a paper when you were really expecting an A. Or you really wanted a specific Christmas present, and you just got socks. There's tons of little disappointments we all have to deal with every day of our lives.
I'm just saying...I don't really do well with even small disappointments. I think it's my unresolved issues with disappointment from childhood (since I never dealt with them) that make me feel like I'm being cut open when I deal with even a small disappointment. I tried to (mostly) buffer myself from most disappointments that I never truly learned how to go through the process of putting things into perspective, moving on and making the most out of the situation regardless of whatever obstacle occurred.
But now that I am having to talk through disappointment with a toddler in a more analytical way about her personal situation, I find myself giving advice that I should be using every time I encounter disappointment. It turns out that she actually takes some of my advice, and she puts it in perspective and moves on. I, on the other hand, don't do it nearly as well.