<prompt> Human: After not having a job for almost an entire year, I finally got a job near the end of the year. I wanted to make sure I can hit the maximum 401K contribution. Im aware that 401Ks can sometimes take a while to set up and Im not ending up in a situation where I dont hit the maximum because timing was a little bit off.I elected to contribute the maximum 90 of my paycheck in the plan. I was pretty sure weird things would happen. I was not disappointed.My next paystub came with a negative number. After 90 of the gross pay went to my 401K, there wasnt enough left over to cover taxes, social security, medical and transportation. Despite having a negative paystub, there was also a positive amount around 90 or so that was deposited into my checking account.A few days later, HR called me to let me know that something weird happened. They informed me that I should expect to see a double charge of medical insurance on my next paystub. She was not able to explain what exactly happened not her job anyway, its accountings job. From what I can tell, company was not able to take out the medical insurance because that would require withdrawing funds from my checking account. Instead, they charged me twice on the next paystub. The negative amount was me owing the company for the extra medical premium.Oh... the weird things that bring me joy.  <response>: I get relocated with benefits a lot. There hasnt been a year where I havent gotten a 100 negative check that doesnt affect me at all. True ups and gross ups get weird really fast. 