I'm not a moderation person. I'm an all or nothing person.

And I guess i should add that I've been lacto-Paleo for 4 1/2 + years now and I have NEVER, not even once, eaten grains or starches in that time. So I guess I'm a bit 'extreme' by some standards. Then again, I'm 150 lbs lighter and have an outstanding improvement in health (asthma GONE, dandruff GONE, rosacia GONE, and I NEVER get sick any more, etc)

Take that as you will. :)

Yes, and I've had to train myself over and over again -- and I'm still wont to slip up and revert to all-or-nothing thought processes -- to embrace the middle ground.

I have OCD, which has manifested as an eating disorder in the past. In order to overcome the ED, I've had to re-evaluate the way I approach food. When I first went Paleo, I tried to be the "perfect" Paleo, whatever that means. I now realize that I function better on a high fat, moderate carb, and lower protein diet (100-115g of fat a day, 85-120g protein, and I fill in the blanks with carbs). Rather than regarding it as me "failing" at being the ideal Paleo, I've instead accepted it as a victory in optimizing my own health and dietary needs.

Oh, and I don't do formal exercise anymore, but when I did? Yeah. Had to do it just right, or I'd be livid at myself for the rest of the day for slipping up and not going according to plan. I'm very laid-back about exercise now, and love taking leisurely strolls whenever the fancy hits me. If I feel lazy or tired, though, I'll cheerfully prop myself on the couch and take it easy for the day. :)

I guess everyone has their different opinion of "extreme". Just eating paleo is seen as "extreme" to most everyone I know. To me however "extreme" (not saying good or bad but just extreme) would be ONLY eating what I've grown, hunted, and butchered myself. That would be cool, but I don't have the means to do that- that would be extreme.
As for exercise... people have told me p90x was extreme (usually people that have never done it), but it's not. I don't do any extreme exercises.
I have 6 kids- is that extreme? lol

I obsess over things like exercise or competition. I rarely miss a workout, but I will sometimes have bad or ineffective workouts when I should have rested. My first outing for a muay thai fight I got beat, so the next time I trained obsessively and sparred far too much to the point where I had been blanked several times in the gym leading up to my next fight...which probably led to why I got KO'ed.

So, I've been learning to work out more intelligently and take time off when my body indicates I should. But, for me, I guess this kind of obsession helps to keep everything else in order in terms of stress and such.

Go big or go home.

Generally I'm pretty laid back and just go with the flow - why stress unnecessarily? But there are times when whatever I am doing gets total, 100% focus. It doesn't matter what it is but nothing will get in the way. It's been described by various people as having infinite patience and perseverance, and dedication. It has also been described by others as downright frustrating and annoying because the focus level usually excludes them totally - even the conversation stops (and I don't do much of that in the first place!)

As has been mentioned on here before, sometimes you just need to do extreme things, either to get something done, to achieve something, or just to let off steam and relax. Anyway, what is extreme to one person is everyday to someone else - free-climbing, bungee-jumping anyone?