On the other hand, you wouldn’t know that Bill Hader was playing Liam Neeson until the very end of the sketch unless you read the description.
This wasn’t a Celebrity Jeopardy sketch where half the joke is seeing celebrities out-of-character and frustrating Alex Trebek; this was basically Hader hilariously commenting on St. Patrick’s Day traditions like the eating of corned beef (in this case, corn on top of a hamburger) and drinking Guinness.
If you watched the sketch without knowing that Hader was supposed to be Neeson, the reveal at the end via the “Happy St. Paddy’s Day” card from “Liam Neeson, Leprechaun, and The Lamb” would have been worth a laugh.