Spin glasses in the mean-field regime with long-range interactions are well understood, but more realistic models with short-range interactions such as in three dimensions remain mysterious. In this talk, we will give an introduction to spin glasses and their theoretical descriptions. Then we review some recent relevant numerical results to argue what they look like from the computational perspective. In particular, we focus on whether there are many pairs or a single pair of states in the spin-glass phase, and droplet excitations are fractals or space-filling. We make analogies with the ferromagnetic Ising model frequently for ease of understanding, and application aspects of spin glasses will also be mentioned.