I don't hate being ISTJ at all. *Shrug* I am who I am, and I'm not going to apologize for it or try to change who I am to fit what others think I should be. With that said, there are parts of myself that I do sometimes get annoyed with. I can definitely relate to wishing I could just cut loose more often, lighten up, and be more reckless and open with my emotions (especially since I'm female)
However, for myself, I figure that when I meet the right guy I will feel comfortable opening up and being vulnerable. I can cut loose when I am around friends I trust and love, and thankfully I can lighten up when it is "play time." Really, it's not worth obsessing over stuff that bugs you about yourself, because trust me, there will always be someone out there that is jealous of and admires/appreciates the qualities and strengths that you do possess.
Just to share for a moment, there was this girl I worked with once...she was beautiful and all the guys at work loved flirting with her. She was always on her phone, was always busy, was kind of ditzy and emotional...but not terribly. It seemed she always got what she wanted -- ya know, a semi-charmed kind of life. However, one day I was working in the back of the store and she was there with me alone. I've spoken to her on occasion, but this particular day she walked up to me and just flat out said, "How do you do it?...How are you always so calm and are able to just be you?...I am jealous of what you have." I'm not entirely sure of the look I gave her, but I was thinking in my head, "Me!? Why on earth would you be jealous of me? You're the one that has it all." Lol...just thinking of that story still cracks me up. So yeah, the grass does always seem greener on the other side. I've learned that it's best to be content with who you are, but not allow yourself to settle into complacency.
Frankly, there are things that EVERY personality wishes they can change about themselves. No one is made with all strengths and no weaknesses (*cough* Yes,thatincludesyou,INTJ's). I think different personalities exist because we are meant to compliment each other and work off each others strengths. Without that variety the world would be a very boring and perhaps a not-so-functional place. So seriously Beat, don't be so hard on yourself...and don't let it get you down that SJ's may sometimes be stereotyped into little neat "personality boxes" that supposedly account for the way we are. MBTI is nice tool and all, but it is certainly not the end-all and say-all of who I am.