Does it take your steem away to upvote other posts?

I am still in my first week here on steemit and have many questions. I won't get into all of those now however one big question I do have is, does it take your steem away to resteem and upvote others.
If it doesn't why do I see really good posts with less upvotes and posts with an image and a line getting lots of upvotes?
Please let me know if you know the answer. Thanks in advance.