Jesus never says that Christians will always be “happy”. Quite the opposite! Jesus tells the disciples that they will have sorrow, that in fact the world will rejoice over the things that cause them sorrow.
Jesus being a shepherd is a familiar idea. It shows up all over the place in the scriptures, in some of the most familiar passages (the 23rd Psalm), or alluded to with some of the most famous people (King David was a shepherd).
There was so much confusion. Mary didn't know what was going on. She runs to Peter and John for help; they don't know what's going on either. Even when the angels ask her what's wrong, Mary's still confused.
Why? It's a simple enough question to ask. Why is Christ forsaken upon the Cross? So that He doesn't forsake you. As much as we might try to deny it or pretend it isn't real, sin has consequences. The wages of sin is death.
Now this was the sort of Messiah the people wanted! It was great. Think of all that could happen if you have a King who could just hand out free food whenever you wanted. The luxury, the ease that we could have!
“What sort of man is this, that even winds and sea obey Him?” The disciples were certainly impressed with Jesus. He had just stood up and rebuked the winds that were roaring on the Sea of Galilee... and they stopped. Things went still. And so they ask, “What sort of man is Jesus?”
So, what sort of people do you fear and hate? Seriously! If you close your eyes and think of a “bad guy”, what sort of prejudiced thoughts float to the foreground? It's just one of the things we sinful folks do: categorize and vilify people. Sin rears its ugly head once again.