I can't center tables in wordpress!

Unless you provide a link to a page demonstrating the problem, no one will be able to offer much in the way of assistance.

use <p> </p>
Example:
<p align=center>table /table </p>

There is likely a CSS Style set in your theme or plugin called ‘table’ (that justifies the location of all tables that do not have another CSS style called). Create a new style and call that one:

Change to:

<table class="tablemine" /*....the rest......*/

Add to theme or plugin CSS:

.tablemine {
     align:center;
/*.....more (copy from existing table style if needed)....*/
}

Often times theme and plugin writers create CSS with a name that may be called in any part of your site which can cause issues. If no class is created called ‘table’ the defaults for the table attribute are used.