diff --git a/blockchain/pool.go b/blockchain/pool.go
index 4016f146c..f4fd1a32b 100644
--- a/blockchain/pool.go
+++ b/blockchain/pool.go
@@ -313,7 +313,7 @@ func (pool *BlockPool) makeNextRequester() {
 
 	_, err := request.Start()
 	if err != nil {
-		panic(err)
+		pool.Logger.Error("Error starting block pool", "err", err)
 	}
 }
 
diff --git a/cmd/tendermint/commands/reset_priv_validator.go b/cmd/tendermint/commands/reset_priv_validator.go
index 34cf78f65..77407cfcf 100644
--- a/cmd/tendermint/commands/reset_priv_validator.go
+++ b/cmd/tendermint/commands/reset_priv_validator.go
@@ -48,7 +48,7 @@ func resetPrivValidator(cmd *cobra.Command, args []string) {
 func ResetAll(dbDir, privValFile string, logger log.Logger) {
 	resetPrivValidatorLocal(privValFile, logger)
 	if err := os.RemoveAll(dbDir); err != nil {
-		panic(err)
+		logger.Error("Error removing directory", "err", err)
 	}
 	logger.Info("Removed all data", "dir", dbDir)
 }
diff --git a/config/toml.go b/config/toml.go
index c6c46d40f..ec70ab75d 100644
--- a/config/toml.go
+++ b/config/toml.go
@@ -13,10 +13,10 @@ import (
 
 func EnsureRoot(rootDir string) {
 	if err := cmn.EnsureDir(rootDir, 0700); err != nil {
-		panic(err)
+		cmn.PanicSanity(err.Error())
 	}
 	if err := cmn.EnsureDir(rootDir+"/data", 0700); err != nil {
-		panic(err)
+		cmn.PanicSanity(err.Error())
 	}
 
 	configFilePath := path.Join(rootDir, "config.toml")
@@ -69,10 +69,10 @@ func ResetTestRoot(testName string) *Config {
 	}
 	// Create new dir
 	if err := cmn.EnsureDir(rootDir, 0700); err != nil {
-		panic(err)
+		cmn.PanicSanity(err.Error())
 	}
 	if err := cmn.EnsureDir(rootDir+"/data", 0700); err != nil {
-		panic(err)
+		cmn.PanicSanity(err.Error())
 	}
 
 	configFilePath := path.Join(rootDir, "config.toml")
diff --git a/consensus/reactor.go b/consensus/reactor.go
index 44206f50f..0eaacefdd 100644
--- a/consensus/reactor.go
+++ b/consensus/reactor.go
@@ -97,7 +97,10 @@ func (conR *ConsensusReactor) SwitchToConsensus(state *sm.State, blocksSynced in
 		// dont bother with the WAL if we fast synced
 		conR.conS.doWALCatchup = false
 	}
-	conR.conS.Start()
+	_, err := conR.conS.Start()
+	if err != nil {
+		conR.Logger.Error("Error starting conR", "err", err)
+	}
 }
 
 // GetChannels implements Reactor
diff --git a/consensus/replay_file.go b/consensus/replay_file.go
index fcab4d038..5c492da39 100644
--- a/consensus/replay_file.go
+++ b/consensus/replay_file.go
@@ -65,11 +65,7 @@ func (cs *ConsensusState) ReplayFile(file string, console bool) error {
 	}
 
 	pb := newPlayback(file, fp, cs, cs.state.Copy())
-	defer func() {
-		if err := pb.fp.Close(); err != nil {
-			return
-		}
-	}()
+	defer pb.fp.Close()
 
 	var nextN int // apply N msgs in a row
 	var msg *TimedWALMessage
@@ -227,7 +223,7 @@ func (pb *playback) replayConsoleLoop() int {
 
 			if len(tokens) == 1 {
 				if err := pb.replayReset(1, newStepCh); err != nil {
-					panic(err)
+					pb.cs.Logger.Error("Replay reset error", "err", err)
 				}
 			} else {
 				i, err := strconv.Atoi(tokens[1])
@@ -237,7 +233,7 @@ func (pb *playback) replayConsoleLoop() int {
 					fmt.Printf("argument to back must not be larger than the current count (%d)\n", pb.count)
 				} else {
 					if err := pb.replayReset(i, newStepCh); err != nil {
-						panic(err)
+						pb.cs.Logger.Error("Replay reset error", "err", err)
 					}
 				}
 			}
diff --git a/consensus/state.go b/consensus/state.go
index b4bfa8783..608d5d2da 100644
--- a/consensus/state.go
+++ b/consensus/state.go
@@ -259,7 +259,7 @@ func (cs *ConsensusState) OnStart() error {
 func (cs *ConsensusState) startRoutines(maxSteps int) {
 	_, err := cs.timeoutTicker.Start()
 	if err != nil {
-		panic(err)
+		cs.Logger.Error("Error starting timeout ticker", "err", err)
 	}
 	go cs.receiveRoutine(maxSteps)
 }
diff --git a/mempool/mempool.go b/mempool/mempool.go
index ef2fa4950..d781500c2 100644
--- a/mempool/mempool.go
+++ b/mempool/mempool.go
@@ -3,7 +3,6 @@ package mempool
 import (
 	"bytes"
 	"container/list"
-	"fmt"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -192,11 +191,11 @@ func (mem *Mempool) CheckTx(tx types.Tx, cb func(*abci.Response)) (err error) {
 		// TODO: Notify administrators when WAL fails
 		_, err := mem.wal.Write([]byte(tx))
 		if err != nil {
-			mem.logger.Error(fmt.Sprintf("Error writing to WAL: %v", err))
+			mem.logger.Error("Error writing to WAL", "err", err)
 		}
 		_, err = mem.wal.Write([]byte("\n"))
 		if err != nil {
-			mem.logger.Error(fmt.Sprintf("Error writing to WAL: %v", err))
+			mem.logger.Error("Error writing to WAL", "err", err)
 		}
 	}
 	// END WAL
diff --git a/p2p/upnp/probe.go b/p2p/upnp/probe.go
index b3056d4cb..d2338b95e 100644
--- a/p2p/upnp/probe.go
+++ b/p2p/upnp/probe.go
@@ -101,7 +101,7 @@ func Probe(logger log.Logger) (caps UPNPCapabilities, err error) {
 			logger.Error(cmn.Fmt("Port mapping delete error: %v", err))
 		}
 		if err := listener.Close(); err != nil {
-			panic(err)
+			logger.Error(cmn.Fmt("Listener closing error: %v", err))
 		}
 	}()
 
diff --git a/rpc/lib/client/ws_client.go b/rpc/lib/client/ws_client.go
index 0b3ec2b8c..bf7709514 100644
--- a/rpc/lib/client/ws_client.go
+++ b/rpc/lib/client/ws_client.go
@@ -353,7 +353,8 @@ func (c *WSClient) writeRoutine() {
 	defer func() {
 		ticker.Stop()
 		if err := c.conn.Close(); err != nil {
-			// panic(err) FIXME: this panic will trigger in tests
+			// ignore error; it will trigger in tests
+			// likely because it's closing and already closed connection
 		}
 		c.wg.Done()
 	}()
@@ -404,7 +405,8 @@ func (c *WSClient) writeRoutine() {
 func (c *WSClient) readRoutine() {
 	defer func() {
 		if err := c.conn.Close(); err != nil {
-			// panic(err) FIXME: this panic will trigger in tests
+			// ignore error; it will trigger in tests
+			// likely because it's closing and already closed connection
 		}
 		c.wg.Done()
 	}()
diff --git a/rpc/lib/server/handlers.go b/rpc/lib/server/handlers.go
index d9ab4790b..a93c6fd78 100644
--- a/rpc/lib/server/handlers.go
+++ b/rpc/lib/server/handlers.go
@@ -720,7 +720,7 @@ func (wm *WebsocketManager) WebsocketHandler(w http.ResponseWriter, r *http.Requ
 	wm.logger.Info("New websocket connection", "remote", con.remoteAddr)
 	_, err = con.Start() // Blocking
 	if err != nil {
-		panic(err)
+		wm.logger.Error("Error starting connection", "err", err)
 	}
 }
 
diff --git a/rpc/lib/server/http_server.go b/rpc/lib/server/http_server.go
index e918192b6..530f90bb9 100644
--- a/rpc/lib/server/http_server.go
+++ b/rpc/lib/server/http_server.go
@@ -56,10 +56,7 @@ func WriteRPCResponseHTTPError(w http.ResponseWriter, httpCode int, res types.RP
 
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(httpCode)
-	_, err = w.Write(jsonBytes)
-	if err != nil {
-		// ignore error
-	}
+	_, _ = w.Write(jsonBytes) // ignoring error
 }
 
 func WriteRPCResponseHTTP(w http.ResponseWriter, res types.RPCResponse) {
@@ -69,10 +66,7 @@ func WriteRPCResponseHTTP(w http.ResponseWriter, res types.RPCResponse) {
 	}
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(200)
-	_, err = w.Write(jsonBytes)
-	if err != nil {
-		// ignore error
-	}
+	_, _ = w.Write(jsonBytes) // ignoring error
 }
 
 //-----------------------------------------------------------------------------
diff --git a/types/part_set.go b/types/part_set.go
index 46387e353..c9a919a9c 100644
--- a/types/part_set.go
+++ b/types/part_set.go
@@ -34,10 +34,7 @@ func (part *Part) Hash() []byte {
 		return part.hash
 	} else {
 		hasher := ripemd160.New()
-		_, err := hasher.Write(part.Bytes)
-		if err != nil {
-			// ignore error
-		}
+		_, _ := hasher.Write(part.Bytes) // ignoring error
 		part.hash = hasher.Sum(nil)
 		return part.hash
 	}