What is the biggest mistake people make when starting to use LINQ? [closed]

Question

What are the fundamental misunderstandings people have when they first start using LINQ?

For instance, do they think it is one thing when it is really something else?

And, are there some best practices to employ to avoid these mistakes?

Answer 1

That it should be used for everything.

Answer 2

Failing to understand the differences betweeen (or existence of!):

.First()
.FirstOrDefault()
.Single()
.SingleOrDefault()

Not understanding deferred execution.

Answer 3

That it only refers to LINQ to SQL

Answer 4

The biggest mistake people make when using LINQ is the same as when people try to use any sort of technology that lies on top of a technology that they don't have any good grounding in.

If you can't understand proper/efficient DB querying, you will screw up with LINQ.

If you can't understand the basic fundamentals of ADO.NET and data access, you'll probably screw up.

People think that by using LINQ it will allow them to coast by, but it won't.