Growing up in the thirties and forties with radio, not to be missed were:
Jack Benny
Easy Aces
Fred Allen
Shows to do homework to:
Not much done to Red Skelton, Bob Hope, Jimmy Durante
More to Fibber McGee and Molly, Amos and Andy
Easily tuned out and more accomplished to The Great Gildersleeve,
    Eddie Cantor
There must have been bad comedians then but either forgotten or never listened to.
Agree with many of the above mentioned bad ones but would further categorize them as dull, narrow, insipid or offensive and would happily turn off Milton Berle, Henny Youngman, Rodney Dangerfield, the Three Stooges, Jerry Lewis, Seinfeld, Mr. Bean, Bennie Hill the Goon Show, Jay Leno (but not Johnny Carson), Woody Allen or Steve Allen for one or the other of the above reasons. I would brook little criticism of Danny Kaye, the Marx Brothers, the Smothers Brothers, Red Skelton, Bob Hope most of the time, Bob Newhart, the cast of Beyond the Fringe, Peter Sellers, Gilda Radnor, Paula Poundstone, Pat Paulsen and probably a few others on a best comedians list.