Smartphones are fun and useful. But they're powerfultools of seduction. Every feature, colour and soundhas been 'optimised' by teams of designers and psychologists to keep you hooked and coming backfor more. And these persuasive designs are not only found in your smartphone, but also tablets, computers, gaming consoles, smart home appliances – you name it. Check out some of the persuasive design strategies below. How many of them look familiar?