Here's an anecdote.
One of the nurses who works in our clinic contracted COVID-19. She follows the same protocols as everyone else, and does not know how she contracted it. Unfortunately, she was initially hesitant to take the Pfizer and Moderna vaccines offered by the hospital to all employees, so she only received one dose before she became ill.
She's back to work now and feeling fine, but she reports that her bout of COVID was just about the worst illness she ever experienced. Severe headaches, muscle and joint pain, and nausea and vomiting so bad that she needed two trips to the ER for IV hydration. Fortunately, her breathing held up, so she did not need a hospital admission. Even after most of her other symptoms resolved, she was so fatigued that she could barely get out of bed for several days. B.1.1.7 is now the dominant strain locally, so even though her sample never underwent genotype screening, this is likely the one that caused her infection.
This nurse is generally in good health. Late 30s, healthy body mass index, and takes only a low dose of one medication to control blood pressure. But COVID still knocked her out for about 2 weeks, and she came within a hair of needing a hospital stay. Now fortunately, she was covered by the hospital's COVID policy that offers full medical leave for any employee that contracts the disease. If she had not been lucky to work as a nurse for a hospital with a generous sick leave policy, though, she would have missed about 2.5 weeks of salary and received two large ER bills to boot.
The take-aways from this case that we can generalize (because they fit with the larger trends):
1) This is not last year's COVID. The new variants are both much more contagious and making younger people quite a bit sicker than the wild type.
2) Despite a case of COVID-19 managing to breech the defenses of our clinic, nobody else became ill. Why? We can never be 100% sure, but most likely because all but two other staff members have been fully vaccinated since March, at the latest, and some of us much earlier. Not only did none of the other staff become ill, but none of our unvaccinated family members got sick either. These vaccines are extremely powerful tools against the virus. This is what herd immunity looks like on a personal level.
3) Even a case of COVID from which the patient completely recovers and does not require hospitalization can cause them to go through hell that they would never want to repeat or wish on anyone.
Get vaccinated!