The reason there are so many is that the airlines are unwilling to include them in the base ticket cost for fear of making it look like they've increased fares. Some are true taxes, but others are fuel surcharges, navigation fees, airport security fees, etc.
The one that burns me is the NAV Canada fee of 56.00 per roundtrip. This fee is the costs the former federal department charges the airlines for running air traffic control, radar, etc. Isn't this a cost of doing business to the airlines ? Why pass it on to the consumers. Can you imagine Coca-Cola selling a 6-pack and adding an extra $1.50 for the plastic holder ?