In the last few weeks I've applied for several student assistant jobs and had 3 interviews last week.
As you know I've been offered a job by one faculty and today I signed the contract.
I also got a call from a different faculty who wanted me to work there. I apologized and said that I accepted a different job.
The lady was seriously pissed..."What? This is unacceptable. Thank you for wasting our time." and then hung up.
I mean, yes, I kinda did waste their time, but they had other applicants (they explicitly told me more than once during the interview) and is it so wrong of me to apply for other jobs and maybe take one if I get the chance and the job seems nice?