Trailing Cr Lf
Trailing Carriage return (\r) and Linefeed (\n) in a varchar are really hard to detect in SSMS.
Imagine there's three columns, A, B and C that have the same content except B has two trailing spaces and C has a trailing '\r\n'.
Select A,B,C from Table
In SSMS the grid will silently turn the '\r\n' into two spaces.
So it will look like B and C both have two trailing spaces.
If you compare A=B it will return
true (because 'A' == 'A ' according to SQL)
If you compare B=C (or A=C) it will return 'false' -- even though A and B will both look (in the grid) like they have trailing spaces.
If you switch the output to text mode, the carriage return line feed will be retained.