Being that stupidity knows no bounds then EMS has no limits, after 20 years I'm still finding people that manage to do something that neither me or my coworkers have ever seen OR heard of before!
Like any job there are good and bad points. If you are a "people person" you will find it easier to talk to people on the worst day of their life. You have to know how to correctly lift a heavy object (some are VERY heavy) using only 2 heads, 2 backs, 4 arms and 4 legs. And most importantly you have to be able to let it all go at the end of your shift, when you start taking this work home with you thats when the big problems start.
You kinda asked a real general question so I tried to give a general answer. If you want to know something more specific ask and someone here will answer