> Which kind of coffee mug is best?

I don't want to open a coffee shop. But I have put some thought about the type of cup I like (not what is scientifically the best).

All this is in context of plain ceramic cups.

First, it shouldn't be too wide. It is an uncomfortable feeling holding such a cup. Relatively taller cups feel nicer to hold. Not sure if that helps with heat retention due to less wide mouth, if you don't have a cover.

Secondly, the handle should be just slightly wider than your fingers wrapped around it. Stupid fancy creative ones are the worst. Overly circular ones are terrible. If your fingers are going over each other while holding it, avoid it like plague.

Thirdly, the inner seam shouldn't be sharp but bevelled. That avoids buildup of deposit. I prefer black but white might be preferable for those particular about cleaning (also see last point).

Extension to previous point: glazed is better than matted - stuff doesn't stick so much.

Fourthly, avoid ones with uneven top/lip. Because you want to be able to put any available plate/cover without the steam escaping that much.

Tip for cleaning cups for lazy people: squirt some dishwasher liquid, fill it up to the brim with water and leave it until your next round. Make sure to hold it low so that the tap water generates some foam due to impact, basically avoid the soap lumped sitting at the bottom. It'll practically wash itself by the time you are back for your next cup and will be much more clean compared to having to clean a dirty cup that has been sitting for a while.