Can someone please explain me why the fuck the following doesn't work in C#?

Dictionary<string,object> mex=Json.Deserialize(data.ToString())as Dictionary<string,object>;
if(mex.ContainsKey("sessionId") && mex["sessionId"].ToString()!=tkn.GetSessionID())

the previous condition is NEVER true, but the following:

Dictionary<string,object> mex=Json.Deserialize(data.ToString())as Dictionary<string,object>;
if(mex.ContainsKey("sessionId") && mex["sessionId"]!=tkn.GetSessionID())

will actually work as expected.

tkn.GetSessionID() returns a string, of course
and mex["sessionId"] is always an object that contains a string in form of a number, like 152, 552, 6246 and so on and no, it won't ever contain any blank or other character

Fuck this fucking shit from C#