Samples are not the -right way- to do things.

Today, once again, I've seen the corruption of code caused by reading code examples and mindlessly parroting the style and not the substance. Every sample you see these days has code that using String.Format for simple concatenation. That's not what it's for, folks! String.Format is to allow formatting (not just conversion to String) and parameter rearrangement. Code like this is wasteful and silly:

private string CreateSelect()
{
   return String.Format("SELECT TOP {0} {1} FROM {2}", this.rowLimit, this.selectFields, this.fromTables);
}

This will needlessly have to scan the format string looking for the replacement parameters {x} and substituting the parameters positionally. This code should be:

private string CreateSelect()
{
   return "SELECT TOP " + this.rowLimit + " " + this.selectFields + " FROM " + this.fromTables;
}

Which C# will actually turn into this behind the scenes:

private string CreateSelect()
{
   String[] temp = new String[6] { "SELECT TOP ", this.rowLimit.ToString(), " ", this.selectFields, " FROM ", this.fromTables };
   return String.Concat(temp);
}

Which is tons faster. This sort of thing is important to get right in the lowest-level of your code, in things like a DAL or UI framework library.
Not that I'm whining...