I want to preface this by saying that I know that I am fortunate to even be having these issues, and that I am grateful for the offer of help, and that this is not about money.
My dad is a builder by trade. DH and I (late 20s) have just bought our first property and and it needs a fair bit of work. Dad assured me that he would be happy to help free of charge and wants to see me happy etc etc. Wonderful, thought naive little me.
His attitude has changed somewhat since I said this was our starter home and we will want to move on in about 5 years' time.
We've not actually started any work yet but we keep clashing over things and it's turning an exciting time for us into a bitter experience.
Everything I want, he will try to talk me out of it. He is basically suggesting doing the house up with neutral basics but I don't want to feel like I still live in a rental. I've had it up to here with black and white and grey and beige and cheap carpets and laminate and putting up with things as they are and trying to show my style and personality through cushions and artwork and other impermanent things. I loooooove colour and patterns and I feel like I've done my time and now I should be able to pick things I like FOR MY OWN HOUSE.
DH doesn't care either way as long as he gets his gaming station set up 
I'm now in a kind of fuzzy headspace where I can't tell if I'm being stubborn because I'm sick of him challenging me on everything and I need to "win" or whether I really do feel very passionately about a certain feature.
Some of the things we've disagreed on:
I want a wooden floor, dad says we should get vinyl or laminate as it "lasts longer"
I want shaker style cabinets in the kitchen with a solid wood counter. Dad says it's too expensive and we should get a quartz or something
I want nice tiles in the bathroom - either a feature wall where the bath/shower is with plain complementary tiles on the other walls, or something a little bit dramatic like one type of tile on every wall e.g. blue squares a la mid century modern. Dad says we should just tile where we need a splashback and paint the rest. I think that looks cheap and unfinished and I don't want it in my house. I don't mind paying for few more tiles.
I want wallpaper in one of the bedrooms, he says we should just paint it.
He will suggest random extravagant things like underfloor heating!
I feel like a petulant child, but I think backing out now and saying that I don't need his help will be like throwing fuel on a fire. My dad is not English either, so helping his children set up a home is a source of great pride and a significant cultural "thing", so I feel extra stuck and annoyed.