Macaulay Culkin -- Smoke Alone Too -

Macaulay Culkin racked up even more "me time" during an introspective smoke and stroll ... while sporting his best grandpa sweater Monday in NYC.

In the "make you feel old as hell" department ... this year marks the 25th anniversary of Mac's breakout role in "Home Alone." The facial hair, cigarette, combat boots, and ponytail hair are sure signs a lot's changed since then -- but the John Hughes classic still holds up.

We'd be lying if we said we weren't jonesin' for a little Wet Bandit action.