Adjusting the volume control was very tricky. Often after nearly 5 minutes loading-time of a bigger programm the display signaled wrong parity. Then you could rewind the tape, adjust the volume-control a tiny step and retry the whole procedure, sometimes several times. :(
Boy oh boy, those were the days. It was especially fun when the volume control wheel got dusty, and every minor movement added loud crackling noises to the process. So for myself that meant adjusting the volume, disconnecting the uplink, playing the tape (to see if it was crackling), then rewind/reconnect.
The most entertaining thing my TRS-80 did was whenever it started to overheat (a couple hours after turning it on), it would randomly display dollar signs ($) along the right hand edge. I still wonder to this day if it was coincidence, or an ironic sense of humour on Radio Shack's part, reminding me of the quality of what I paid good money for..... 8)