My mum wanted to bf my older brother but was given rubbish advice by her HV (feed for 10 mins on each side every 4 hours etc) and never got her supply properly established so had to ff from 8 weeks or so. After this experience she was determined to succeed with me and had read the book Breast is Best in preparation (it was the late 70s). When the MWs asked if she was feeding 10 mins each side every 4 hours she would smile and nod but then when they left the room she let me feed as much as I wanted. She fed me until I was 2.
When I was pg with DS, she (and my dad - though they are divorced - and my gran) were all very pro-bf and keen to encourage me to do it. I'd always assumed I would try, but took a couple of emergency cartons into hospital just in case it didn't work out. I don't remember being that bothered either way, really. Luckily, DS latched on beautifully from birth and I only had a tiny bit of soreness at the beginning.
By the 10-day check, DS had lost 8% of his birth weight and the MW made me feel really shit about it. I came home in tears and suddenly what had seemed so easy and natural became really hard and frustrating. By this point I was determined so I battled through the next week, with the reassurance from a bf peer supporter on my local LLL helpline and lots of research on MN. It was on here that I learned about 'catching down' (DS had dropped two centiles from his birth weight but stayed on that curve until he went onto solids) and that weight loss of up to 10% is normal. By the next appointment DS was slowly gaining weight and we were discharged by a nicer midwife who told us that his weight loss had been completely normal and nothing to worry about 
We're still going at nearly 9 months and DS has never had any formula. Having not been that bothered before he was born, I've become very pro-bf and am very interested in it politically (currently reading The Politics of Breastfeeding). DS was unsettled from birth and until very recently was an appalling sleeper, to the point that I suffered from PND. Many people advised me to stop bf so I could get some sleep, but I couldn't bring myself to. It felt like the only aspect of motherhood that had come easily and naturally, and I loved the fact that I could calm and relax my jittery, hectic baby by feeding him.
My biggest influence was a friend of mine, who was the first person I'd really seen breastfeed. She fed in front of us so nonchalantly and made it look so easy and natural. If it hadn't been for seeing her do it I probably wouldn't have felt so comfortable feeding in public.
Like others have said, I'm lazy, forgetful and disorganised, with an intense dislike of washing up, so ff was never going to be for me. As a matter of personal preference (and with no judgement on the decisions of others) I also try not to give DS anything I wouldn't want to eat myself - I've found most baby food I've tasted gross (as has DS) and it looks like poo, so I generally just give him normal food. In the same way, I prefer to eat fresh food and wouldn't choose to drink powdered, processed milk, so haven't expected DS to, either. However, if bf hadn't gone well, I would have been extremely grateful that I lived in a society where a viable substitute was easily available.
Feel free to quote me if any of this is useful.