Unfortunately, the answer is yes. No matter how much observing you do, you won't really know whether you like the work until you start seeing patients (2nd or 3rd year of D school) and you won't really know whether you like the workflow until after you start in practice. There are plenty of disgruntled dentists out there counting the years to retirement.
- If you like to do detailed fiddly work with your hands, thats a good sign.
- If you have empathy but also a little bit of a thick skin, that's a good sign.
- If you like to meet people and are comfortable chatting with strangers, that's a good sign.
- If you like supervising people, that's a good sign.
A lot of dentists are "naturals" with #1 (suited for the procedures). But note that this is only a fraction of what makes you well- or poorly-suited for the profession.
Many dentists quickly learn #2 (not letting patients' fears and anxieties weigh on you), but not all.
Most dentists aren't naturals at #3 (relating well with patients), in my observation, but it can be learned with time and experience; this rather than actual hand skills often separates successful dentists from unsuccessful ones.
Most dentists are not naturals at #4 (management skills), receive no training in it during dental school, and many never learn to be good managers. Thus the management side of private practice probably causes most dentists the largest share of their stress. In any case private practice seems to be slowly giving way to corporate or group practice, so you may have less management responsibility than did past generations of dentists.
There are certainly exceptions, but I think that most people find, as the years go on, that dentistry isn't really a PASSION; but it is reasonably interesting, challenging work that serves a meaningful purpose and affords a lot of independence and autonomy. Many (most?) would choose the same career again and many choose to continue practising at least part time for years after they could have retired.