Hi Marie, thanks for posting your images.

I'd like you to know this isn't meant to be a negative critique, I would just like to illustrate a point about the use of photographic (blur in this case) effects by referring to your shots...

First, for the sake of discussion we (in this thread) would do well to be clear about what perspective we're talking about when discussing these "effects." Professional (commercial) standards are one thing -artistic is another.

From an artistic standpoint, the artist's intention and artistic expression dictates the use of "effects" and the extent of that use. After all, its the artist who is making the photographic statement, he/she can choose to accommodate art-buyer preferences (whatever these may be) or not depending on whether or not the artist is concerned about image sales and the degree of comfort the artist has in accommodating these preferences without impinging on his/her "artistic integrity."

From a professional, marketable, standpoint, clients have standards they impose which dictate an image's "acceptability" and therefore the photographer's image success. Editors, publishers, art directors, have their own variances in what they will accept or not, but in general there are a few basic guidelines/rules to go by for aspiring pro-photographers.

In the case of photo-effects, including blur effects, usually less is more. And usually, they want the subject in focus with the exception of motion blur to illustrate a key aspect of the subject and the image (i.e. the race example earlier in this thread).

Looking at the rodeo images, there are the following observations:
If the RODEO is the subject then the blur of the entire frame can be effective in showing the action of not only the bull rider, but also clowns and excited spectators. However, having something in focus (non-blurred) like the sponsorship signage or the stadium railings would make it more acceptable to the viewer's eye (which looks for the stability of a visual "anchor" of sharp focus). Otherwise, in the circumstance of providing this image as illustrative or editorial use, it looks like a photographer mistake or technical shortcoming.

If the rodeo RIDER is the subject then blur of the bull and rider is expected and highlights the tremendous energy associated with the scene. However, as in the case above, its good to have portions of the image in clear focus, non-blurred. In the case of the rider being the subject more clear focus image real estate is desirable, to further focus attention on the subject.

An interesting technique, especially in lower ambient light situations, is to combine flash with a slower shutter speed. The flash will stop action of the subject, the slower shutter speed (set properly) will allow enough ambient light to register to give a motion blur effect. If you set the flash strength properly and the shutter speed correctly you can balance the flash effect so it is only slightly noticeable, resulting in an image that highlights the motion of your subject, clearly displays the subject, and doesn't "over-effect" the background.

Keep on shootin'
and having fun!

...my two cents