"When the only tool you have is a hammer, everything looks like a nail."

In UI designs, you are tempted (or even required) to use the UI controls tool kit which is provided to you. This can lead one to follow guidelines blindly and build useless interfaces using the latest controls, but it is also a guideline that leads to better productivity. You need to use what you have in order to get done quickly. 

The problem comes when other principles aren't invoked to balance this. We've all seen VisualBasic apps which are a nightmare of listboxes, tree views, and check boxes. 

See GuiGuidelines for related principles, patterns, and truisms.

----
This also applies to architecture.  Oh, this problem clearly needs an Oracle
Database to solve!
----
Also there's the old IBM consultant's line: "I don't know what the problem is, but the answer is CICS, COBOL, and DB2".
----
There's a Dilbert strip that illustrates the above point about architecture.  It depicts various folks at a meeting.  A problem is presented, and each meeting attendee suggests a solution that just happens to match their personal "hammer" -- weighted cash flow analysis, etc.  In the final panel, a porcupine is sitting at the end of the meeting table and declares, "We must stick them with quills! It's the only way!!"
----
And don't forget the important converse:  if you don't have a hammer, very few things will look like nails.
------
See also: EatingSoupWithaFork