Eli Parker was a very good friend - he and Grant met when Grant was a clerk in his brother's store in Galena, so they went way back. It's funny - Grant was dealing with some drunk who decided he wanted to fight Grant. Parker asked Grant if he needed some help. The drunk cussed and turned around - there was a very large Indian looming over him...not smiling. He left!
To me, Badeau was another example of a virtue of Grant's that too often became a fault. He would stand by someone even if warned they weren't very worthy of his loyalty and trust. Sherman thought his pal was naive, but I tend to think Grant preferred to see the good in people. It often came back to bite him.