Artifacts:

Sometimes artifacts may be present in peripheral blood smears.  It is important to be able to differentiate these from real inclusions or true bacteria or signs of disorders in peripheral blood.  Some common artifacts include fibers from things like alcohol pads or gauze, precipitated stain or crystallization of stain, bacteria in peripheral blood mistaken for stain, drying artifacts in RBCs, which produce bubbles in cells or crenated cells, necrotic cells that are blebbing and breaking down (karyocytosis or karyokinesis), broken and smeared cells due to harsh staining preparation, or platelet satellitism.  See the images below to see what some of these artifacts may look like. 

Fiber in a red blood cell peripheral smear;By Bobjgalindo - Own work, GFDL, https://commons.wikimedia.org/w/index.php?curid=5653558

Stain crystallization

Bacteria (streptococcus) in a peripheral blood smear (true infection).Public Domain, https://commons.wikimedia.org/w/index.php?curid=2740643

Necrotic cell exhibiting "blebbing" as nuclei break up into fragments (apoptosis and karyorrhexis)

Images of Platelet Satellitism: 

Platelet satellitism occurs when platelets stick to or adhere to neutrophils.  This typically happens when blood is collected in EDTA (lavender-top) in rare individuals, which may lead to a falsely low platelet count.  This issue may be resolved by collected the blood in sodium citrate instead.  

By Paulo Henrique Orlandi Mourao - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8792971

By Guy Waterval (Own work) [Apache License 2.0 (http://www.apache.org/licenses/LICENSE-2.0)], via Wikimedia Commons

By Osaretin - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=51158894