Trucking companies are finding that the distraction provided by shifting is a contributor to accidents, while independent owner-operators (75% of US drivers) will give up their shifter when you pry it from their cold, dead fingers. Note, though, that modern truck shifters will have a hi/lo range and Overdrive splitter, allowing there to be only 6 positions in the shift pattern including reverse. However, many older trucks would instead have two gearshifts (Often 4 or 5 gears on main stick, 3 or 4 on auxiliary) you'd have to work at the same time, often requiring you to let go of the steering wheel!
Vehicles built to race are almost always manual transmissions, as they have customarily provided advantages for control, weight savings, low parasitic power loss, reliability, and fuel efficiency. NASCAR racers have a four-speed h-pattern with reverse like a street car. Grand Tourer (GT) and Lemans race cars usually have semi-automatic transmissions, which utilize a simple up-or-down lever that shifts up and down sequentially with no clutch. Formula 1 and IRL take this further with electronic paddle-shifters placed behind the steering wheel, mostly to save space and keep hands on the wheel. Many open-wheel racers don't have reverse, and thus need to be pushed to go backwards (Formula 1 rules require the presence of a reverse gear). The only types of racing in which automatics dominate are 4X4 truck racing, where the rough terrain and frequent airtime would destroy a solid transmission without constant shifting and clutch work, while a fluid-coupled automatic can soak up the jars and jolts all by itself, as well as (certain classes of) drag racing, where specialized automatics can deliver reliable starts at high RPMs, as well as shift reliably and quickly at the right points of the powerband.
Problems can begin with being unable to start the vehicle (put it in first gear with the clutch down first.) Then, a careful pressure must be applied to the gas pedal while letting off the clutch (keeping it a bit at a halfway point, "the bite", that is particularly difficult to master). It requires a keen touch to get this right, and unpleasant results may occur by: a) using too much gas and too little clutch, burning the clutch b) if on an incline, using too much clutch and too little gas, jerking or stalling c) not fully engaging the stick with the clutch in, making a "grinding" noise and heavily wearing the synchros (not the gears, which are always engaged). Once moving, switching between gears is fairly intuitive. It is possible to cause thousands of dollars of damage to a car in seconds if you're not careful, though: for instance, if you downshift to 1st instead of 3rd and don't catch the clutch before realizing your mistake: the engine will be forced by the speed of the car to rev far past its redline, damaging the engine's valvetrain as well as the clutch and the synchros due to the huge speed mismatch. Some cars do have a "locking" feature which prevents the driver from returning to first or reverse gears until the vehicle has come to a stop.
Note the ease by which a driver could throw an unfamiliar transmission into reverse — Someone who learned on an H-pattern shifter (left image, above) will become used to having the forward-left corner be first gear, but when driving in a car with the other common pattern (right image, above), that position is reverse instead.note Another common variation is "dog-leg first", with the same shape as the traditional H-pattern, but forward-left is reverse, and back-left is 1st gear. Some vehicles have a button or lever to stop accidental reversing, but this is not universal practice, nor always effective. Lastly, a number of American cars had Reverse requiring a "J motion" where the stick shift had to be pushed in and then moved. Finding reverse in a Volkswagen is even harder — legends have sprung up around finding reverse in a Volkswagen.
For added fun, let's throw in the semi-automatic transmissions (similar to the abovementioned system used in GT cars), which are like a shift stick, only without the stick (usually with buttons or paddles instead, though some still use the "stick", only it just goes up or down and not in the H-pattern); on consumer cars, this is an option on some automatics selectable by the driver. If you are used to manual, it can be a blessing as well as a curse, when you start wondering where your left pedal has gone.
A note to those who are just learning to drive stick: you are going to get a lot of contradictory advice from more experienced drivers. Some say engine braking is the way to go, while others say it's cheaper to replace your brake pads every few years than to make a mistake and do some serious damage. Some say it's fine to stay in first gear and use your clutch to keep from rolling backwards on an incline, while others say you're going to wear it out faster that way. Some say it's okay to run at higher revs in a lower gear, while others say you're going to kill your gas mileage (and quite possibly your entire engine) that way. And the list goes on. In the end, the best way to handle this is to smile politely, thank them for their help, and then find the driving style that works best for you. If you do something wrong, be assured that your vehicle will let you know.
If you are driving a vehicle without synchromesh, you need to "double clutch", or change from one gear into neutral, fully release the clutch, adjust the engine speed with the accelerator, and only then engage a different gear. Inexpert attempts to do this can seriously damage the gearbox. Non-synchronized gearboxes are sometimes called "crashboxes" as even experts can't help grinding their gears sometimes. Oddball shift patterns can complicate things even further.
As of this writing, however, new heavy-duty automatics are standard in transit buses and even starting to appear in full-size semis. Surprisingly this trope is not shown very often when a character has to drive a motorcycle. Far more motorcycles have manual transmission than automatic, however motorcycle gears are typically linear in nature making it difficult to, for instance, shift from first to fourth and send the vehicle leaping forward into something painful. It is still possible to forget the clutch, forget what gear you're currently in, accidentally hit neutral or fail to hit it intentionally (as it is often an awkward 'half shift' between first and second gear).