I'm not really that familiar with the concepts of unconditional parenting, I've bought a few parenting books but never found one that really works for me.
My two yr old is extremely strong-willed, she's starting to calm down now. With relation to the opinion on dentists etc. My daughter took one look at our dentist and burst out crying so I tried to cheer her up but he wasn't that bothered, just said, 'no point in forcing her', had a little play with the mirror and give her some stickers and advised to bring her back in six months. I felt a bit disappointed as I really wanted to know how her teeth were doing. But what can you do? You cannot physically restrain them on the dentists chair and I don't believe in shouting or getting cross as in my daughters reaction, she was just scared of a new situation, not being naughty.
At the height of her tantrums, we went on holiday to visit friends in Austria, involving two flights each way. It was a total nightmare, she would not wear her seatbelt for taking off or landing. A few of the air hostesses were a bit arsy about this, they could clearly see we were struggling with her, however a lovely male hostess came over and just said 'I think she'll do what she wants to do' and give her some sweets. Left us to it, and they continued with their take-off procedure.
So finally, negotiation, reprimanding, being tough, being soft... it really depends on what sort of child you have and what stage of development they are going through. Now my daughter seems to be turning a corner and is emerging into a little darling with an amazing sense of humour, not always perfectly behaved but hey-ho. And I'm not that fussed about being the 'boss' either, as long as I guide her in the (sort-of) right direction.