In 2007, the genome-wide association study (GWAS) era began in earnest with the successful identification of the first loci influencing type 2 diabetes and obesity risk that were robustly replicated. Since then, hundreds of loci influencing type 2 diabetes and obesity risk, as well as relevant quantitative traits (e.g. BMI, glucose and insulin levels), have been identified. These successes have been empowered by the aggregation of data across multiple cohorts and datasets, through meta-analyses conducted within the context of large international consortia. In parallel, efforts focused on identification of mutations causative of rare extreme phenotypes have revealed additional genes that impact energy balance and glucose homeostasis. In my talk, I will summarise what we have learned during this journey: what we have found, what we have not found and what new biology we have learned. Is the cup half-empty, or half-full, and where do we go from here?