[xpath] XPath - Selecting elements that equal a value

In Xpath, I am wanting to select elements that equal a specific value.

Sample XML data:

<aaa id="11" >
    <aaa id="21" >
        <aaa id="31" ></aaa>
        <bbb id="32" >
            <aaa id="41" ></aaa>
            <bbb id="42" ></bbb>
            <ccc id="43" ></ccc>
            <ddd id="44" >qwerty</ddd>
            <ddd id="45" ></ddd>
            <ddd id="46" ></ddd>
        </bbb>
    </aaa>
    <bbb id="22" >
         <aaa id="33" >qwerty</aaa>
         <bbb id="34" ></bbb>
         <ccc id="35" ></ccc>
         <ddd id="36" ></ddd>
         <ddd id="37" ></ddd>
         <ddd id="38" ></ddd>
    </bbb>
    <ccc id="23" >qwerty</ccc>
    <ccc id="24" ></ccc>
 </aaa>

Now, using the XPath:

//ccc[.='qwerty']

I get the correct, expected results:

Name    Value
ccc     qwerty

Now, using the XPath:

//aaa[.='qwerty']

I get unexpected results:

Name    Value
aaa      
aaa     qwerty

And what I am particularly interested, is how to select any element with that value

XPath:

//*[.='qwerty']

I get very strange unexpected results:

Name    Value
aaa
bbb
ddd     qwerty
bbb     qwerty
aaa     qwerty
ccc     qwerty

Can someone explain these results, and how to fix my XPath expressions to get more expected results?

Try

//*[text()='qwerty'] because . is your current element