B737-800 Captain reported concerns over maintenance practices at a station that caused unnecessary delays and aircraft refusals.

Narrative

I've noticed major lapses in safety on the ground in ZZZ and significant issues when dealing with maintenance in ZZZ. During this flight we had a return to gate due to a sink leak in the lav that caused a flooded E&E bay and multiple electrical faults. During troubleshooting; ZZZ maintenance continued to operate the weather radar with personnel standing in front of the aircraft and were dismissive to myself and the First Officer who were trying to explain the safety implications. We went outside multiple times to ask ground staff to stay away from the front of the aircraft. After they were done 'troubleshooting' they left the radars on and when I asked them to turn the radars off they did not know how and were changing the modes on the radar as opposed to using the glare shied control. I expressed my concern re: the probability of water in the E&E bay and electrical faults after the lav issue and had to argue to get a maintenance worker to open the E&E bay. He finally agreed; then walked off the aircraft and sat in his truck; so I opened the E&E and at least a gallon of water fell from the door; with moisture all over inside. I told them I would refuse the aircraft due to water intrusion in the E&E and dispatch communicated with maintenance control to down the aircraft for a proper inspection. After they 'fixed' the radar/PWS the aircraft would have momentary wind shear alerts parked on the ground and the PFDs displayed conflicting information; but maintenance did not seem to understand the problem (just hitting the master caution to cancel alerts) and were dismissive of my concerns. We were called by the company to go inside the building for safety and we turned the aircraft over to maintenance. After 10 hour rest; we returned to the airplane and found the aircraft with the APU running (all night per the ground crew) without any fuel pumps running and a 1200 lb. fuel imbalance. All hydraulic pumps were left on. Multiple switches were in improper positions. The wet towels and toilet paper we used to soak up the lav water from the day before were still on the aircraft; and although the water system was deactivated there was no hand sanitizer or wipes provided on the aircraft. During preflight we discovered the PSEU light on and took a further delay for troubleshooting. On the prior flight into ZZZ (ZZZ1-ZZZ; DATE) my seat did not seem to fully lock in place and would significantly wobble side to side. I wrote up the seat in ZZZ and when maintenance came on the aircraft he was extremely angry I wrote up the seat; telling the company rep on the airplane to 'cancel the next flight' and they needed the hot spare because he needed to find and install a new seat. This was before I had exited the flight deck and he hadn't even looked at the seat to understand the issue or see if it could be serviced. His behavior seemed inappropriate to the First Officer and I who discussed the situation on the way to the hotel. I'm concerned someone is going to be injured by the disregard for standard; safe practices in ZZZ and I find it concerning obvious maintenance issues are not taken seriously. As a pilot; I should never be chastised for writing up discrepancies or raising concerns as to the airworthiness of an aircraft or questioning the safety implications of a procedure. We need a thorough review of the ZZZ station and maintenance procedures; as there's a serious risk of safety issues or aircraft damage.