Continuing the epidural subject...
Dentist example is a bad one. A dental anaesthetic does just that - takes away the pain. Epidural, OTOH, as lil said, can slow down labour, potentially leading to further interventions. Not even mentioning that more often than not, you will be on the bed flat on your back which is not good. Pushing baby out whilst on your back increases chances of tearing, as you are working against gravity and putting extra pressure on the perineum.
Why should a woman "try" to endure pain, when we never ask anyone else to do it under any other circumstances?
Because labour pain is good. Pain is the body's way of communicating with us. It hurts more in certain positions. So your body is telling you to move. I had to lie down during examination which was excruciating. DS's heart rate also dropped while I was on my back. I wouldn't have felt it if I had an epidural in. And the MWs probably would have picked up the dropping heart rate so would be keen to get him out Asap. When all that was needed just to change a position.
Of course if it hurts like hell and you feel like you can't do it anymore then go for it. But I think so many women these days actually forget that it's supposed to hurt.
Anyone considering water birth - go for it. It's amazing. And if you don't get on with it, you can always get out of the pool.
And I would recommend hypnobirthing (hypnotic hinge???) too. I haven't done it myself but my brain just transported itself to some parallel universe itself. I was so calm the MWs didn't think I was in active labour until I asked them to examine me and I was 9cm 
Sorry for an epic mega essay. I'm a bit tipsy and it's an emotional subject!