Being an American taxpayer is fine and dandy if you never plan to live outside the us again; but if you aren't, it's a very expensive and labour intensive deal; your home country bank will fire you as a customer because of FATCA, the reporting requirements to the us are insane (FBAR and every single foreign transaction needs to be reported), and your e.g. Pension savings and other holdings likely become a losing proposition because they are PFICs.
Most people ignore these issues, but almost everyone is liable under the us tax code, and especially with the just announced sharing of NSA data with the IRS, it will all be legally documented for the IRS to pursue.