Ignorance: The Wonderful, Terrible Can:

Oh the wonderful, possible, terrible things people can do with the word 'can'.  That, and its misuse.  The word 'can' means 'to be able to' or 'to be permitted to'.  Typically, however, people use it in place of 'will' (meaning in this case 'expressing future tense' or 'expressing the inevitable'), or in the place of 'should' (meaning 'used to indicate obligation, duty, or correctness, typically when criticizing someone's actions' or 'used to indicate what is probable'), or in the place of 'may' (meaning 'expressing possibility' or 'expressing permission').  These uses can be confusing to the layman, who might think they are requesting something to be done, and are instead asking if it is possible.  Case in point:  You can jump off a bridge, but should you?  You may want to reconsider that.  When someone asks if they can do something, they should be intending to ask if someone has the capability to do so.  I often tease co-workers on this when they ask if I can ring up their purchases, replying that 'I can, and would you like me to do so, since that's not what you just asked'.  Usually this leaves them confused and I explain the difference between 'can', 'will' and 'may'.  They may have their purchases rung up after asking, and I will ring them up if I can.  It's not that hard to use can as one should, but many may be ignorant to its use and most can and will incorrectly use it.  If you understood that last sentence without problem, congratulations, either you knew the correct use already, or you came to understand it after reading this post.  If you still don't know how to use 'can' correctly, please insert yourself in a goto loop back to the top of this post and reread it until you do understand.  It isn't very difficult to understand, but its frequent misuse may be confusing.