Err, how did one find out "who" their guardian angel was from reading their palm?!
But aside from that: If someone reads your palm as totally negative, diss them. NO-ONE's future is totally negative, or totally set in stone either. Often what shows up in the hands is signs of potential to be (or what has been). It's not always clear either - for example someone can have a lot of "children" lines, but not have kids of their own (but they might be a teacher or something, ie they have lots of kids in their life). If someone tells you REALLY SPECIFIC things, they either have a lot of balls, or they're trying to scab easy money off you.
Shell: If you have lots of lines on your palm, chances are you have an air or water hand.
This can indicate (but may not neccessarily be totally accurate, particularly if the lines are weaker on your "active" hand than the other) that you sometimes get caught up with thoughts or emotions before actually coming to a conclusion/executing an action
Essentially, it means that there's some "static" going on - you probably tend to think a bit before rushing into anything (whether bad or good).
Fire and earth hands (less lines, often more distinct as well) on the other hand tend to be "do more, think less" type people.
Additionally you have to remember it's folly to just look at ONE element - you gotta look at the whole hand to get a clear picture. It's like trying to judge a person based on one attribute, you can't say for sure that they're stupid just because they're blonde
If they're carrying a law textbook under one arm, that kinda says they mighe be smart - the combination might also suggest that they're a little sensitive to blonde jokes etc etc. Look at the whole picture peoples