Blame science. 

For many people coffee is their lifeline, they can't wake up properly without it, can't function past lunch time unless they have a second cup, and could never do a late shift without having another. And while a lot people complain to their friends about having too much coffee and promise themselves they'll cut down or give up, it may be a lot harder for some people than others. This is all because of science. According to Body and Soul, Scientists at the University of Edinburgh and University of Trieste in Italy (the home of the biggest coffee addicts) researched 3000 people's coffee habits, along with their DNA. The results found that those with a specific genetic make-up are more likely to be addicted than others. Researches found that some people have a gene called PDSS2 which reduces the body's ability to break down caffeine. This means that coffee stays in the system longer which quenches any cravings. People who do not have that variation of the gene have a metabolism that breaks it down faster, so you don't stay satisfied for as long. So essentially if you don't have the genetic variation, you are more likely to crave a lot more coffee, so if you just can't shake the addiction and are drinking a coffee as you read this, it's not your fault, blame it on your genetic make-up!