What mistake do most new hires make in their first week?

Over confidence

Making the mistake of mentioning or pointing out the racism, bigotry, sexism, hate speech, behavior & actions of others that they haven't realized yet are untouchables & mentioning their words & behavior will get you attacked, threatened & run out of a job.

Talk excessively about a previous job or how this job differs from their last one. Brag about what they do on days off or before/after work.

Not asking key questions about their job, dress code, cell phone usage etc ...

Tardiness (failure to allow for rush-hour traffic is common!), failure to make effective notes for future reference, etc. High on the list of other shortfalls are errors in on-boarding paperwork, esp. missing details for benefits (SSAN for beneficiaries, having details for Direct Deposit, incomplete mailing info, etc.)

Missing work and being late.

Not saying the right things to the customers

Getting frustrated because they can't remember everything.

Calling out or not showing up

Afraid to ask questions.

Assumptions of all kinds: that the organization hired him because they wanted him, that the new peers will help him figure the ropes, that professional standards are up to par

Show their poor work ethic

Try to change or do too much. They need to observe and learn.

wrong sales

Taking off & coming late

Not managing their expectations.

Electronic devices.

maybe try to show themselves in a very intrusive or hard way.

Not asking enough questions.

Not submitting requirements and going AWOL or miss training

Trying to hard to be liked; just be yourself....

Not listening and learning enough, trying to show what they know rather than getting the lay of the land before trying to establish their place in the landscape. And complaining, which should NEVER happen in the first few months of any new job.

Trust his boss

Not showing up

sales people learning how the product works when they should be learning how to solve customer business problems

Thinking they know how to do their job properly without any feedback on how to do things

Trying to know all and wing it...

Being late

Know it all. Just try to get along

None. Typically new hires are very very cautious.

Not asking enough questions, or interacting with their immediate coworkers.

Fear to ask questions comes to mind. If you fear looking like a fool by asking a question, you're likely to show that you are by not being ready for the situation.

Thinking they know everything. Our software is intuitive and basic functionality is easy, but there are so many different use cases and configurations that it takes a long time to fully understand

being too confident

Not asking enough questions and trying to do the work without fully understanding what’s expected

Learning Mistakes

Don't ask enough thoughtful questions.

Negotiating for a different title, more money or perks... didn't you just accept the job? Title and compensation discussions should always be finalized before you start. Focusing too much on the step-by-step processes to learn the big picture, or vice versa.

Wanting to learn to much to soon, Leads to making mistakes.

Not asking enough questions.

talking too much and not listening enough - and not asking questions when they are talking.

Lack of engagement or expecting work to fall into their lap than asking questions and eagerness to work on things they want to work on

Not learning the names of their coworkers.

don't ask enough questions

Not asking more questions

Overthinking

I don’t think you can say anything a newbie does during the first week could be a huge error

too little interpersonal interaction with new colleagues

Act like they know it all / don’t ask questions and really listen to the answers

Being too timid and too overly observant. Conversely, being too impatient, aggressive, or critical. Also please for the love of God, refrain from referencing, "Where I used to work..."