Why might a monopoly or a trust in a certain industry be bad for both customers and workers?

Skilled workers in such an industry have to work for the trust/monopoly or not work in their skill set. This gives the employer much leverage in pay/benefit negotiations.

Since consumers have no choice but to buy from the trust/monopoly they have to pay (usually) higher prices than they would if there were competition between businesses owned by different people.

Without competition there might be little incentive to improve product quality and to develop new products.

consider an orange peel: if you want to try and lay it flat, you have to stretch it, we know exactly how things are being stretched or squashed at any given point. we have many different map projections because each has different patterns of some projections can even preserve certain features of the earth without