bakfed
There's absolutely no requirement to get letters from your current boss; in fact, all adcoms know that some folks will not be able to obtain letters because of the potential repercussions from current boss. Don't worry about this and just get two great letters. You will, however, need to explain this in your optional essay but trust me, you're not the only one and adcoms would be okay with it.
Wow, that's a big relief!
But do you think that if, for example, I've only worked at 2 jobs - my current job and my previous job. I have great experience at my current job and will look to capitalize on my current work experiences in my essay and interviews... but the fact that I don't get a recommendation letter from my current boss, will that be a 'weird signal' to the adcom's that maybe I'm hiding something? Will they look at this negatively in any way?
Thanks so much!
Personally speaking, yes, I think it'll be a bit weird for you to harp on the pros of your current job but aren't willing to obtain a letter. However, going back to the original issue that there will be people who love their current job but are afraid to ask for letters (again, repercussions reasons), it's not uncommon. It's really something that you just briefly touch on in the optional essay and it should suffice.