Busses at the end of the night can be crowded and busy.
Here are some helpful hints to make it less:
-Leave prior to ending of night time entertainment (fireworks, etc.)
-Walk around the park and do some shopping prior to leaving
-Go on one last ride (can usually get a fastpass for a ride)
-Use Uber, Lfyt, Taxi, Minnie vans
-At Magic KIngdom you can see the Kiss Goodnght
Again, relax and enjoy the ride, you are almost home.