Miserable is sort of a catch all term.
Temperature wise, someone in that tank is unhappy. If you've got a heater the odds are the goldfish feel like they're sitting in a house in the middle of summer with no AC. If you don't then the tropicals feel like they sitting in a house in winter with no heater. They're not in danger of death due to temperature but they are out of their comfort zone and not happy. They'll be stressed, the temperature won't give them a disease but the stress on them will make them much more susceptible to catching something.
Space wise the fish will get crowded. You've got three fish in there that are going to get big. In fact the shark (can you get a picture of him?) if he's a bala (very shiny silver) could get big enough that his nose could touch one end of the tank and his tail the other. The goldfish are going to get big enough that they'll take up a big chunk of the space all on their own. They won't be able to get away from the other fish or relax. You're not likely to see any normal behaviors when they are this packed together. Some fish get more agressive, some hide more, none of them will be happy. This crowding will stress the fish as well. Stress weakens their immune systems and... disease.
Waste wise, again you've got some very big fish in the tank that will make lots of waste. Now if your biofilter can eventually grow to handle them (and that is a VERY BIG if) you're going to be on a razor's edge. With that little volume of water per fish even the slightest upset in the biofilter can lead to a huge ammonia spike and potentially dead fish.
As it was said, happier healthy fish will be brighter in color, more active, and much more robust. We're not trying to be downers but what you've got going is not likely to end well and in a tank that size you're not likely to lose one fish you're likely to lose them all if something happens. The goldfish need to go back as does the shark. Guppies can make for nice fish to watch and if you don't want to deal with the babies then either the male or female need to go back as well. It's rough, its not fun, but its for the best. There's a lot you can do with a ten gallon tank that will still be sustainable and you'll enjoy. In a few years when you've got a few more bucks you can get yourself a tank and have some goldfish in an environment that can support them.