here are some from my own observations, in no particular order:

- incestual relationships with other union groups: unions can only hire other union workers when they need work done in a field where their workers do not have any specialty. e.g. - if you work for UAW and you need your building remodeled, only union carpenters and electricians, etc can be hired. this is meant to show solidarity with other union workers, but ends up costing extra in the short term. these things should be up for competitive bidding, imho. let the union workers compete with non-union and take the least expensive, best quality option. if the union is slightly more expensive but has considerably higher quality work, fine. if the work is equal, it should go to the most cost-effective bid

- protectionism: if your facility is a union shop, you CANNOT have ANY non-union people do work, even on a volunteer basis. i had the occasion to work on a convention in a union convention hall and some of the people in our crew had worked on a different convention a few weeks earlier in the same hall. they said the union tacked on several tens of thousands of dollars because people wanted to help clean up and started stacking chairs to help the regular crew. the union bosses charged extra for it because they wanted to punish people for helping out. sometimes, people just want to feel helpful, they should not be punished for their volunteerism.

- inflexibility: i think unions sometimes move too slowly to keep up with the business needs of the companies they work for. part of this is because their bargaining agreements last years and part of this is related to the protectionism i mentioned before. i don't think workers should keep giving up pay and benefits so that CEOs can give themselves bigger and bigger bonuses, but i also don't think unions should completely rule out the changing climate when they go into negotiations.