Sorry it is difficult to trust almost anyone in the trades. It is easier to do the work myself and not deal with strangers in and around my house. When I have to hire someone I tell them up front that I'll be checking every detail, pay extra to purchase the materials myself, and if they don't want the job - well good! I always fine someone who will work with me as I pay a bonus for that.
The psychological effect of green is largely dependent on the tone or hue. Some green hues create a positive, natural atmosphere. However, darker hues or pale olive green can seem militaristic or ill. Multiple shades of green can serve different purposes and set different moods. Maritime greens are ideal for studios and offices as they inspire concentration, while cool forest greens can be used in bedrooms and bathrooms.
