I don't know that I have an answer for you but I do know that "yee haw" thing and I love it. I should probably consider entering that 12 step program with you if I want to get serious about AX again.
I can tell you this. My attitude towards autocross changed after about 3 years. Partly my heart wasn't into the competition aspect, just playing around and experimenting with car control and yes, having fun and yee haw happens.
My 2nd and 3rd year I was competing with my friend/mentor/competitor in equivalent cars with equivalent levels of mediocrity. It was a blast. Yee haw was not on my mind. Driving as hard and well as I could was it. Competing with my best friend in a completely different car with pax just never really seemed to make sense to me. I figured he had pax on his side driving a ringer car on cheater tires. He gets it with AX, I only have moments. Once my competitor in class quit and I didn't really have direct in class competitor I just started having fun and playing. That was the end. I didn't care about times and figured for 5 minutes of fun I would yee haw the living crap out of the car. Plus I want to push it over the edge and play catch and release. I was priming myself for track and wanted to know what the car felt like when it went out from underneath me on AX course first.
Doing track immediately removed the yee haw nonsense out of my system and go me very focused. Also, as James notes, self preservation says don't yee haw, we're going to damn fast to do that.
So maybe I could suggest you get one person in your class, riding together, compete together, push each other to get that much better. Your focus tends to get pulled in the right direction to meet your goal. With the lack of goals, you just drive around. I have found my best sessions in HPDE are when I have a preset goal for that session and/or weekend. Just arriving to drive and have fun gets seat time, but not necessarily good learning time.
This year I will try and drop the yee haw attitude and focus (or at least try). I'll be co-driving something different and don't plan on letting the car owner trash me every time. He's thinking right now he'll just kick my ass every event cause I won't try. Let's just keep that our little secret. Beating him in his own car and seeing a grown man cry is way more satisfying than a fridge magnet
Not sure if that helps at all. Maybe I should just try rallyx too!