diff --git a/src/client.rs b/src/client.rs
index d7b3f1f..63e4d8f 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -73,7 +73,7 @@ fn wrap_stream(stream: TcpStream, _domain: &str, mode: Mode) -> Result<AutoStrea
 fn connect_to_some<A>(addrs: A, url: &Url, mode: Mode) -> Result<AutoStream>
     where A: Iterator<Item=SocketAddr>
 {
-    let domain = url.host_str().ok_or(Error::Url("No host name in the URL".into()))?;
+    let domain = url.host_str().ok_or_else(|| Error::Url("No host name in the URL".into()))?;
     for addr in addrs {
         debug!("Trying to contact {} at {}...", url, addr);
         if let Ok(raw_stream) = TcpStream::connect(addr) {
diff --git a/src/handshake/server.rs b/src/handshake/server.rs
index d389fd3..fbd08b6 100644
--- a/src/handshake/server.rs
+++ b/src/handshake/server.rs
@@ -18,7 +18,7 @@ impl Request {
     /// Reply to the response.
     pub fn reply(&self) -> Result<Vec<u8>> {
         let key = self.headers.find_first("Sec-WebSocket-Key")
-            .ok_or(Error::Protocol("Missing Sec-WebSocket-Key".into()))?;
+            .ok_or_else(|| Error::Protocol("Missing Sec-WebSocket-Key".into()))?;
         let reply = format!("\
         HTTP/1.1 101 Switching Protocols\r\n\
         Connection: Upgrade\r\n\