IMO 18" gap from counter to bottom of cabinets is too low I like 20 -21" gap I think now tiny little piece of trim painted to match the cabinets if possible and the ceiling it not possible .

Ok, I think it would have to be glued somehow to the top of the cabinet. I did find some tiny little wood strips online. I would have to just cram it in there; there is no room for nails. Thanks!

Can you repaint the ceiling the cabinet color?

Yes, but it the shadow just makes that gap very apparent sadly.

The title made me think, "One quarter inch? How bad could it be?" But, yeah, it's the shadow that makes it a problem. You need just the smallest piece of molding. Maybe even small quarter-round ... it won't really "show", but it'll remove the problem.

honestly i think you have to learn to live with it.

Caulk just behind the face of the cabinet will hide the shadow line

Many years ago when we built i chose to have my uppers mounted 24” above counter at ceiling. there is a similar gap between top of cupboard doors and the ceiling. i’d never really noticed before today.

I think it's trivial. Shadows are going to be cast on the ceiling by the much larger doors anyway.

Oh no! So sorry I mentioned it!

It isn't trivial to you and it is your kitchen and your project. Don't be afraid to ask for ideas!

I’d be just as annoyed as you are. Paint the small piece of wood you found to match the ceiling and no one will know it’s there. I think it will camouflage the problem well.

Fill with backer rod, caulk and then paint to match ceiling.

It’s not bad. Would a strip of 11/16 primed cove molding from your local big box store allow the cabinet doors to close? Tack it to the ceiling. Think of it as a teeny-tiny crown. Cost will be <$10 per 8’. There are other styles of tiny molding. Surely one will work. Good luck.

I would use instatrim. https://instatrim.com/ 

It doesn't specify on the website, but lowes lists it as paintable and I used it above a shower years ago and painted it to match the walls and it worked like a charm.

Never tried it in a high traffic space, but for your application I think it would work perfectly, just like it did for my shower.

[if anyone tells what a backer rod is, thanks]

Backer rod is a synthetic ropey material that you use to plug a gap that's a little too big to just stick a lot of caulk in there. Then you put the caulk over it.

Float the ceiling down. PIA, but it's fixed.

I have this same issue and I learned to live with it. If you add trim, it needs to be so thin and possibly flat or your cabinet door may have an issue shutting completely.

Tack a piece in place and see if it works before buying more.

I agree with njmomma about the trim not lying flat. Also, if your ceiling is not perfectly flush, you will still wind up with a tiny gap above it in spots.

I suggest caulking all of it instead. It's a big gap, so you'll need backer rod. Mask it and use a spatula to get it flat. Instructions here.

Any "bug" of any kind that makes it into your home will find that crack.

Consider a (much smaller than traditional molding) corner trim strip.

https://www.lowes.com/pd/0-6693-in-x-8-ft-Painted-Composite-Wall-Panel-Moulding/3401982?cm_mmc=shp--c--prd--mlw--ggl--LIA_MLW_122_Mouldings-Specialty-Millwork--3401982--0--0-_-0amp;ds_rl=1286981&gclid=EAIaIQobChMIsta8p6yg9AIVy-DICh2f0Q4tEAQYAiABEgKZdfD_BwE&gclsrc=aw.ds

Paint it the color of the ceiling so it is a part of the ceiling rather than a part of the cabinets.