why do you think this isnt serious?? i think its great! neutrals dont make a painting serious. i think if you can paint like this with colours you should keep it up! i would love to see more!! i paint the same way. no specific subject. just let the paint and the brush do what it wants and let ur emotions control!
if you wanna do neutrals (although i think ur great with colour) why dont u put out the neutral colours u would like to use, theen put the other paints away so you dont get tempd to use them. and just paint as you would do.
you should attempt and then post what you come up with!