At my old company we would ban customers that were repeatedly abusive to customer service agents. Agents had the right to hang up on customers that were being abusive and if the same customer kept getting reported, eventually they would receive a letter from the legal department telling them to stop. If it continued, they would get banned.
I remember one guy was so bad that a director got the phone system to automatically route any calls from him to his mobile line and put him in his phone book. He would very politely greet him by name as soon as he picked up the call to make it clear that he wasn’t ever going to get through to anyone else.
I would do a search for job listings that would be the jobs you would be applying for if you chose to leave your job or were laid off. Do the job descriptions list the certifications you are thinking about getting? If so, it might be worth pursuing, especially if you can get your current employer to pay for it.
For example, almost every project manager job lists PMP certification. If you are currently a PM and don’t have it, you might want it just in case you get laid off to improve your chances of getting a new job. Otherwise, you might be up against 10 other candidates with just as much experience, but 3 of them have a cert and you don’t even get a screening interview.