I always carry the necessities on board in a carryon - medicine, makeup, swimsuit, any valuables and a change of clothes. Everything else is packed. I always tip the porter about $5 or so for the two bags I check and I have NEVER run into a rude porter. As in all professions there are a few bad apples that spoil the whole bunch. I also think our attitude has something to do with how we are treated. I always smile, say good morning (or afternoon) thank them and wish them a good day. Works wonders!
For those who have had a really terrible experience, I am sorry - as I stated above there are few bad apples in EVERY profession: doctors, nurses, cops, teachers, executives, etc.