Fishing is one of those skills that a lot of people would say is "boring".
I guess I agree to an extent, in that I am not one who can sit there and spend an hour or more at a time fishing, but fishing DOES provide its own unique joys.
Inconsistent Rewards Keep You Coming Back
If you've ever learned about Reward Mechanisms in life, you've probably learned that the most reliable way to get someone to do some particular thing over and over is to give out rewards inconsistently - that is, have the action linked to the reward in such a loose way that the reward may not come as a result of the action each and every time.
This is the theory behind the "psychologically addictive" qualities of gambling, especially when it comes to slot machines. The action is putting in cash and pulling the arm. The inconsistent reward is the feeling you get when money is won when the symbols line up right.
Fishing's Inconsistent Rewards
Fishing has consistent rewards and inconsistent rewards, depending on what you're looking for at the time.
Consistent rewards are common fish - fish that you can cook to advance your Cooking skill or you can feed yourself or your Hunter pet to reduce general playing costs.
Inconsistent Rewards come in many forms: Fish, Scrolls, Potions, Equipment, Locked boxes and boxes that aren't locked are common things in the Old World, and once you get into Outland there's Allakhazam was busy or this item does not exist. Click to search again. ',VAUTO,HAUTO,FULLHTML);" onmouseout="return nd();">Mote of Water and various types of vendor trash to help keep cash funds up (ever caught a Allakhazam was busy or this item does not exist. Click to search again. ',VAUTO,HAUTO,FULLHTML);" onmouseout="return nd();">Golden Vendorfish in Outland? grey, and sells for 6g each).
Why Fish?
The main reason my toons fish is because it actually bothers me to walk past a puddle of floating debris (or whatever it's called in whatever zone you're in - the names change by level and zone) and not be able to fish it. I've fished such great things out of those pools in the past (including things that sold for up to 100g in the AH) that I've spent a lot of time making sure my various toons have fishing trained up so they can take advantage of the pools.
A secondary reason my toons fish is that when they get to Nagrand at around level 64-65, the lake just behind the city has pools of Pure Water, and those yield a greater amount of Allakhazam was busy or this item does not exist. Click to search again. ',VAUTO,HAUTO,FULLHTML);" onmouseout="return nd();">Mote of Water than other spots do - and Mote of Water sells REALLY well on the Auction House if you're not going to use it yourself for materials for your professions.
People Provide Relief To The Boredom
So, I stood in Ferelas for a couple of hours over a couple of days of 10/20 minute fishing increments and got my fishing from 229 to 275 or so before I headed to Terrokar Forest in Outland to continue skilling up on fish I'd be more likely to use myself.
One thing I noticed was that each time I went fishing, eventually someone would see me and come by and visit - for a minute or two generally, but one fellow Troll Mage actually stayed and chatted with me for about 20 minutes before sauntering out on his way while I fished.
Funny, his conversation with me was mainly about how Mages have the most ridiculously disconnected outfits and how Troll Mages look like total dorks.
We were both standing around in our Ninja costumes for that discussion, so I guess his point has some merit ;)