[axisK]

In the short term you'll probably end up feeling guilty about it but it's much better to work somewhere where you don't hate the environment.

Before I started my current job, I already had an accepted offer from another company (Company A). While I had some regrets about accepting the first offer too quickly I put it down to the second company (Company B) reacting slower and that they should probably have moved a bit quicker if filling the position was really a priority (they're interview process took much longer because the CTO was on holiday during the process).

Eventually I did start working at Company A but realized within the first day that my co-workers had almost no passion and some of them had very questionable work ethic. After two weeks I contacted Company B and asked if they would still be interested in me working there and had the difficult conversation with my manager. At some point one of the directors had me explain to a client that I was leaving by my own choice - to this day I'm not even sure what this accomplished.

I ended up being much happier at my current company and didn't have to work in an environment that I hated.

Close friends even commented on noticing a change in my demeanour within the first few days of starting at Company B.

Overall while I would do it again but I think it's also taught me to be careful when accepting a position as well as that it's much easier to rescind an accepted offer before you've started adding value to a company than resigning afterwards.