Regarding happiness, I'll give you an easy litmus test: if you strongly consider surgery as an alternative, anesthesiology may be good for you (and a surgical subspecialty even better). If you're more of a medicine person, stay away. This is a knee-jerk surgical specialty, in real life, regardless how "intellectual" it looks from the outside. That's why it can be practiced solo by CRNAs.
Many people you will deal with in your professional life will be surgical quality arses, mostly simple-minded arrogant mediocrities, whose intellectual level maxes out at gossip, bad jokes and yesterday's medical knowledge (the type of emperor that wears no clothes, surrounded by the typical court). These will also be the people who will pass judgment on your skills and knowledge, but especially on everything else that shouldn't matter (but it does). This is a job where artistic impression matters more than technical merit (because nobody outside the specialty has a friggin idea about what you really do), where advanced practice nurses can do 90% of your job and few people really appreciate the other 10% (beyond being the malpractice lightning rod and safety net for anesthetists), where technological advances don't empower you to provide better care, but a safe way for the bean counters to replace you with cheaper cogs (the next couple of big ones will probably wipe out anesthesiology as a medical specialty).
And if you are considering anesthesiology as a stepping stool to CCM or pain, remember that anesthesiology has always been the ugly unwanted stepchild of CCM (and has been treated accordingly by the job market -
here's the SOCCA job database for ya), and that pain reimbursements are at such a low that there are possibly more pain-boarded people practicing anesthesiology than pain (which probably applies to CCM, too).