Biggest mistake that impacted my career was not having a "rolodex" or keeping up contacts with people I met over dozens of projects my first decade.
Biggest whopsie as a 15 year old building servers was starting a server with case covers off to check whether it boots, then dropping a screw on the exposed hard drive board. It left a neat trail of sparks and smoke as it bounced down. 200mb full drive of insurance company data burned in front of my boss watching.
Later in career, different place different times, my colleague and best friend ran a mistyped grep on prod server that tried to suck up all of the files content redirected into a single file. AIX in my limited experience is an unbelievably robust system - but it does Not handle root disk out of space well. Or at all.
This is probably my worst error as well, one that I've kept repeating for over 20 years. Making the effort to maintain professional relationships over time, especially when inconvenient, is the number one piece of advice I'd pass on to anyone new to any field. Sending a "how's it going" e-mail every so often cost nothing. It's the one thing I've emphasized to my own kids repeatedly. Hopefully they'll do better at it than I did.
Biggest whopsie as a 15 year old building servers was starting a server with case covers off to check whether it boots, then dropping a screw on the exposed hard drive board. It left a neat trail of sparks and smoke as it bounced down. 200mb full drive of insurance company data burned in front of my boss watching.
Later in career, different place different times, my colleague and best friend ran a mistyped grep on prod server that tried to suck up all of the files content redirected into a single file. AIX in my limited experience is an unbelievably robust system - but it does Not handle root disk out of space well. Or at all.