Most golf courses don't host pro tournaments. So for the No. 18 hole, it depends on who's planning it.
Public golf course managers like for the final hole to be easy: If Joe Everyman finishes with a par - or a birdie - he's more likely to play our course next time. (An owner told me this, I don't know how true it is).
Some courses built before World War II had a "round wrecker" final hole, supposedly to challenge the golfers. The Meadowlake public course in Enid, OK, once had a brutal No. 18: 240-yard par 3 across the lake, with deep bunkers on sides and back. Old timers (in 1980s) told me half the players would pick up after dumping balls into the lake on No. 18. Course eventually changed its finish to a crisp, and dry, 380-yd. par 4.
Normandie Golf Club in St. Louis, build by Robert Foulis circa 1901, is the oldest public course west of the Mississippi. He put in a par 3 No. 18, about 250 yds. from the back tees. Lots of players will lay up to avoid deep greenside bunkers, and then try for up and down. Green is nice and smooth once you get on it.
As far as tournament courses go, a stern No. 18 can be birdied by a good shot from the pros. But, pin-hunting incurs a risk, and you can get a bogie or worse if you miss. Also, an easy No. 18 would probably increase the likelihood of a three- or four-way playoff on Sunday.