The color of mug that makes coffee taste better is pink mugs.
Also the rounder the mug the better the coffee taste is as well.
Coffee tastes better in ceramic instead of stainless steel as ceramic does not absorb or impart flavors in the coffee.
Stainless can impart stainless steel flavor into the coffee and can change the coffees flavor.
The reason diner coffee mugs are so thick is so that they don't break as easily as thinner mugs.
Diner coffee mugs are built thick to withstand the rough conditions in diners and resist tipping and was designed that way when used on military ships so avoid breakage.
With demand for electrical insulation jobs slowed by the war, Victor won the contract and began producing a coffee mug with an unglazed ring that helped the coffee mug resist sliding on Navy ships, curved sides that were easy to grip, and a heavy build that prevented cracking.
The thicker diner mugs also help to keep the mug of coffee warmer.
The more mass it has the more heat it will absorb, eventually reaching a point of equilibrium where it's able to retain enough heat to keep the coffee warmer for a longer period, a thicker ceramic cup will fare better.
Ceramic mugs are a wonderful way to drink warm tea or coffee because they are thick enough to hold the heat of the beverage without burning your hands.