Beer before liquor, never sicker; liquor before beer, you're in the clear. The drinking rhyme everyone learns young, treated as folk science: get the order of your drinks right and you will dodge the hangover. Different drinks, the logic goes, do different damage depending on sequence.
The order makes no difference, because every standard drink contains the same intoxicant, ethanol, whether it arrives as beer, wine, or spirits. Your body does not care what order the ethanol turned up in; what determines how drunk and how hungover you get is the total amount of alcohol, how fast you drank it, your size, and whether you ate and drank water along the way. Researchers actually ran a controlled trial on this, splitting volunteers into groups who drank beer then wine, or wine then beer, and a third group sticking to one; the order had no significant effect on next-day misery. The rhyme survives because it is catchy and because people who switch drinks are often just people who have had a big, long, mixed night, which is the real reason they feel terrible. So the running order is irrelevant. The volume and the pace wrote the hangover, not the sequence.