Before you flag it as a duplicate I think my situation is a bit different from others I've read on here. I am currently in school studying for comp sci and was supposed to get co-op job this summer so I canceled my planned trip to Europe. Now for reasons co-op never happened and I was stuck with nothing to do for the summer. I applied at places and got a job at a warehouse. The job is pretty dull and boring and I feel like I'm losing IQ working there. Now I got a job offer from a pretty big ISP to work in tech support but the catch is that I have to start immediately. I would really like to give a 2 weeks and quit properly but unfortunately that'd not an option. If I get the job at the ISP how should I go about quitting the warehouse on the spot?
If you have decided to leave the same day, regardless of the fact that you will have burnt a bridge you do this:
"Boss, thanks for the opportunity but this isn't for me." Then hand him a piece of paper that you resign effective immediately.
If they've given you anything (work clothes, id or security badge, etc) then make sure you have it with you at the time you are quitting. Ask the manager what process you need to follow from that point.