Serious question for nurses: why do you use huge ass needles and not IVs for bloodwork?

I have to get bloodwork often. I told the nurse at the lab that I want it taken from my hand and she said they don't do that for bloodwork very often because the veins are smaller and it hurts more. I told her she needed to do it from my hand today and the nurse told me that for the bloodwork I was getting, she couldn't do my hand. I told her she also needed to use an IV but she said they can't do that. I told her to use a butterfly and she said she will use the gauge necessary but she can't get blood from an IV.

I tried telling her she was only getting my blood from my hand but she wouldn't do it so I walked out. I argued with my doctor that she needed to do it at her office, but she said that they don't have the ability to do that.

I have a complete workup and something from my arteries but I don't know why they refuse to take it from my hand! Sure it will take longer but I hate bloodwork from my elbow.

Why don't nurses listen to their patients? If I want something done a certain way, they need to listen to their patients!

And none of you can give me a real reason why you can't listen to your patient. I know what I want and if I tell you to use a butterfly or IV in my hand, listen to me. I know my body best. To tell me you can't use a butterfly needle or an IV for what I'm getting is ridiculous. I'm just so pissed off with this and I'm 30 weeks pregnant too so I'm extra grumpy lol