Parents imposing the wedding they want on us?

Since we first started wedding planning both our parents have imposed their wedding ideas on us and it has got to a point they are hijacking our wedding. It is different from what everyone else seems to go through, other people's parents seem to want bigger and better for them but ours keep trying to downplay our wedding plans and convince us to go cheaper and smaller than we are. It really hurts my feelings. It is like they are saying we don't deserve anything nice and they have really stepped on our toes with their ideas. My parents put a lot of pressure on us to just have a backyard pizza party and forget a more traditional wedding and his parents have been telling the guests to dress less than casual or in costume and to not expect much. This has been going on for a long while and we have talked to each of our parents but it doesn't stop. Our wedding is already pretty small and on a budget so it's hard to have all this pressure to make things cheaper, it's not possible. Has anyone else experienced this? It is causing us a lot of stress just would be interested to know how others handled the same situation.