I believe you should never skimp on art, real original art - buy what you love, what touches you and makes you smile. If you have a modern interior then you'll probably lean towards contemporary, expressionist, abstract art and if you have a traditional interior you may prefer landscapes and more traditional realist or impressionist art, BUT, you don't have to. Nothing is more striking than a large colourful abstract piece in a traditional setting or a beautiful, ornately framed painting in a contemporary room. If it reflects your personality, what you love and defines your space as uniquely yours, then go for it.
It's your art. Find what you love, the pieces that speak to you and forget about rules.
Artists' break rules all the time.
Pablo Picasso said “Learn the rules like a pro, so you can break them like an artist”.