Likely not for a full 20 seconds but for several seconds definitely. Sometimes I'm evaluating a beer (competition setting, to give feedback to a fellow brewer, or analyzing my own product) and the visual gives me useful information as part of the whole. If it's a beer I made sometimes I'm not so much evaluating it as saying to myself "Job well done old boy - that's a thing of beauty!" But also I just enjoy looking at a beer. May sound weird to some but I think beer is beautiful - I appreciate the colors contributed by various grains, think about the recipe that went into the glass of beer I'm holding, think about the art and skill of the brewer, a yes just enjoy the hue of the beer be it a garnet, deep brown, orange amber hue, crystal clear golden, or cloudy yellow. Holding a beer up to allow a light source to shine through it allows me to see it's true color, unmuted. I'm surrounded by beauty and I pause to appreciate it from time to time. In my case this is not done to impress anyone - I generally try to be self aware and not be a pretentious bore but also don't hide the fact that I know a bit about beers and like to take time to appreciate them. I drink first with my eyes.