Annoying in that I'm not smart enough to get my head around it!
These are a few common categories of もの as a sentence ending particle as explained by one of my texts. It is an expression capable of expressing different types of emotions including desire, reminiscence, excuse, admonition, command, conviction or exclamation and is used to help relate an abstract event or situation in vivid, concrete imagery.
1. Plain past form of the verb + ものだ is used when the speaker is reminiscing about the way things used to be.
学生のとき、毎日のように、パチンコをやったものだ。
2. At other times, もの seems to add nothing more than emotional intensity to the statement.
私もその山に登ってみたいものだ
3.This construction is also used in making generalizations, particularly when the speaker is expressing a strong impression or conviction.
友達はいいものだ。
4. ものだ is also used to express what one must or should do. The negative form ものではない expresses what one should not do. In more formal speech もの can be replaced with べき(べからず)
大人だったら、そんなことをいうものではない。
5. At times, ものだ functions like から (because). The difference is that the former is used when the speaker is trying to make an excuse or trying to justify an action or opinion. ものだ、から are sometimes used together.
仕方がないでしょう。バスがなかなか来なかったんだもの。。。
6.The construction ものだ is a protest against undesirable conditions or against what the speaker feels to be unreasonable expections...not very polite...use with caution...etc etc.
Sorry I'm running short on time but in brief it's very close to the rude English expression "Do you expect me to....?"