The comparison table is the part I will keep coming back to. The same input, 1e20, gives four completely different answers depending on the language: Java clamps to Integer.MAX_VALUE, JavaScript's bitwise shortcut wraps into garbage, C leaves it undefined, and Python returns the exact integer. That makes the point better than any single warning could — there is no universal "cast" behavior to rely on. The detail that surprised me most is the Python caveat at the end: int() is exact, but the float itself only carries 53 bits of mantissa, so by the time you call int() some precision may already be gone. The billing-engine example drives the practical rule home: check the value against the destination range before casting, and reach for BigInt or BigDecimal when precision cannot be compromised. One question: in your experience, is the JavaScript bitwise case the most common real-world bug here, since val | 0 looks like a harmless idiom until the data grows past 32 bits?