I've never had much of a problem keeping fish or corals. That being said when I was younger I really enjoyed going and buying fish and corals, now it is probably my least favorite part of the hobby.
It's stressful these days buying livestock, both fish and corals. So many pests, invasive algaes, diseases have become more and more aggressive over the years. I don't enjoy the process anymore, I love all my animals very deeply and am very hard on myself (as I should be) for loosing and organism in my care, no matter their place on the food chain. I also don't want to purchase something I know nothing about so I am definitely not an impulse buyer. I also grew up working in this industry at a LFS and saw first hand how many people jump in feet first into this hobby and go overboard right away. I think the biggest/most important asset in this hobby is patience, fear of purchasing new livestock can actually help replace patience. (So that's kind of a plus).
I also am an artist and don't like looking at a 50 gallon tank that has 300 frags in it. I have a 200 gallon tank, people think that is a giant tank, but it is really still really limited space. So not buying new stuff all the time isn't a bad thing. I mostly enjoy watching my corals grow and change, I do enjoy fish, but my love has waned over the years. Marine fish can be a real heartache at times, and their behaviors/personalities can change over night. I'm writing this after hunting down and catching a very large angry purple tang from my display that just up and decided that he loved Micromussa Lordhowensis ALOT. It took me 5 days, but he is off to his new home. This is honestly not a new feeling I have had, once I started keeping corals I really fell in love with them, fish took a backseat and the corals became the priority.
Corals have been an adventure too. LPS are no sweat in my book, SPS are a whole other world of "worry and panic". Such fleeting objects of beauty that you can spend hundreds of dollars for a tiny nub, you can love and grow that nub into an amazing colony, beautiful and perfect in it's own unique way. Then wake up the next morning and they are all gone! I love them in everyway, but hate them in everyway, knowing that they likely won't be there forever and their demise ultimately will be my fault (more than likely). Kinda a tough pill to swallow after throwing thousands and thousands of dollars into little tiny nubs. But hey, it's a relaxing hobby!