Before anyone starts, I don't want to hear about my decision being selfish as millions are out of work etc. because nobody knows how I feel atm.
Anyone who calls you selfish for quitting your job is an idiot - we don't live in some kind of dictatorship where people are forced to work, and it's not as if by resigning you are preventing someone else from taking that job (probably the opposite in fact).
Quitting your job may be many things.... foolish, brave, smart or whatever, that's not my place to comment - but it certainly isn't selfish.