The pathogenesis of acute thrombosis, either arterial or venous, is typically multifactorial and involves a variety of factors that may be considered relatively "innocuous" when present alone. When someone is unlucky enough to accumulate several risk factors, compounded in many cases by one or more acute triggers, that person may be propelled over a threshold that precipitates the development of an acute episode of thrombosis. There is now reliable evidence that acute thromboses (both venous thromboembolism and acute coronary syndrome) follow a typical seasonal pattern and particularly display a characteristic spike during holiday periods. Overindulgence and abrupt changes of several lifestyle habits have been described as potential precipitating factors during such periods. Long travels, unhealthy diet, excessive or binge drinking and eating, decreased or increased physical activity, emotional and psychological stress, might all variably contribute to trigger an acute thrombotic event. Although the real causes of this "holiday phenomenon" remain speculative as yet, there is a widespread perception that they might represent preventable events like several other risk factors of both venous and arterial thrombosis. Beside drastic and unrealistic measures, such as canceling such holidays from the calendar, it seems reasonable to at least provide advice to patients about these "dangers," especially those individuals believed to be carrying a higher risk. Many (if not all) patients may ignore such advice and carry on regardless, but they should be given the benefit of informed choice.