As DM, I do not consider that my job is to kill you - it's to create challenges for you to overcome in a way that makes a great story. Death is a risk, sometimes a strong risk, especially if you are doing something stupid (YMMV on what constitutes stupid, of course). Without that risk, however, there is no story worth telling. I know people get very attached to their characters (at least, I get very attached to my characters) but it's a dangerous world and sometimes the dice just don't go your way. That said, there's absolutely no fun in a TPK.
Rules matter, and I generally play by RAW (or RAI if RAW is blatantly stupid); but so does narrative, fun and the rule of cool. Sometimes I'll simply have forgotten/overlooked a rule, which is usually a consequence of having played too many gaming systems, rather than early-onset senility (I hope). In such cases, I'm happy to be reminded of what the rule is and (depending on seriousness) will either retcon or play on with the understanding that in future the rule will be properly followed.
In terms of maps, I was originally firmly against, partly since I do most of my posting from my phone (except at weekends), but also because I have traditionally preferred that old standby known as "Theatre of the Mind". However, my recent experience of DMing PbP has shown me that some sort of map really is indispensable; I will therefore do my best to provide them, with the understanding that I can only update them from my computer which will slow things down slightly.
