Being only 21 and very fortunate I've not had many (any) of the devestating difficulties some posters have alread mentioned (thankfully) but my life has changed a lot and there are things that have impacted me.
1) I was an OCD hand washer as a child, couldn't go more than a couple of minutes without washing - my sleeves were always wet, my hands red raw and bleeding but it taught me that I can control what I feel I "need" to do I know it's under control. It taught me how to recognise when a behaviour is getting out of hand.
2) Aged 15 I got with WandA, long distance and a little later moved school - it was one of the toughest periods (losing all my friends, struggling to make new ones and not having someone supportive near by as I couldn't really talk to my parents) but I got through it and now I can recognise when I'm "spiralling" into negativity and can avoid it.
3) Realising painful penetration was always going to be a part of my sex life. I learnt that my OH is truly amazing for understanding and I learnt that sex isn't just about penetration or orgasm (I find orgasm painful too). I was in and out of specialists offices having biopsies, botox injections and various other treatments before realising this is just what I have to deal with and really, it's not so bad! My sex life is better than it would have been thanks to the pain and I wouldn't change it.
4) Aged 18 I was diagnosed with a permanent, untreatable chronic pain and fatigue condition - it's taken a long time to come to terms with it but I now realise we can't grumble about the hand we're dealt because nothing changes, we are who we are and we have things to deal with but noone is going to make your life better - you have to do it yourself. For the sake of your own happiness. We only live once, we can't let things get in the way of our happiness.
5) Joint biggest impact on my life so far - moving to be with my OH, starting university doing a degree I love, realising what I want to do with the rest of my life and learning to work bloody hard and self motivate (in high school I was the worst at avoiding work - spent a year and a half of two year courses doing nothing) and achieving what I want to. Getting on to my PhD. Knowing I deserve it thanks to my passion, enthusiasm and hard work. Feeling more confident than ever in my abilities and finally, finally, making my parents proud!
6) The other biggest impact - losing religion. I am a happier, more relaxed person now I realise it's silly to think we get another chance at this, we have one life, we have to make the most of it and enjoy it and not sit around worrying what some make believe superhuman sadistically wants us to avoid. Why would I want to spend my life regretting and avoiding the things that make me happy...
The two happiest things I've discovered are science and skepticism and I don't believe God is compatable with those beliefs (I know there are scientists who disagree but this is my opinion). I think losing God makes me more responsible for my actions and my happiness and I'm very glad, and proud to call myself an atheist (or as Richard Dawkins puts it: a "temporary agnostic in practise").
Adx