Most people who are surprised haven't done their homework.

Read their web site. The additional fees are pretty clearly stated. Do not book through an OTA, as they often do not clearly let you know the options.

Consider purchasing The Works, if you need it. It pretty much covers everything you would expect (except for in flight refreshments)

You may find another carrier less expensive.

Sign up for the emails. They have very frequent very attractive sales. Once you buy it you are locked in.

If you can travel with a backpack you can escape all of the fees but your party may not be seated together.

It is cheaper to check a bag that carry one on.

I have always purchased the lowest possible air fare and a seat assignment. I've never been charged an additional fee except for the Fat Tires I buy on board.