Put the summary of the bug you're having here

What I expected to happen was...:
I expected the game to load when I opened it

What actually happened was...:
it opened and then crashed an I got a crash report
detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

– Head –
Thread: Client thread
Stacktrace:
at atk$a.c(SourceFile:166)
at atd.j(SourceFile:119)
at atd.f(SourceFile:130)
at atd.F_(SourceFile:308)

– Block entity being ticked –
Details:
Name: minecraft:piston // atd
Block type: ID #34 (tile.pistonBase // atb)
Block data value: 0 / 0x0 / 0b0000
Block location: World: (-9482,238,2305), Chunk: (at 6,14,1 in -593,144; contains blocks -9488,0,2304 to -9473,255,2319), Region: (-19,4; contains chunks -608,128 to -577,159, blocks -9728,0,2048 to -9217,255,2559)
Actual block type: ID #34 (tile.pistonBase // atb)
Actual block data value: 4 / 0x4 / 0b0100
Stacktrace:
at ajq.k(SourceFile:1484)

Stacktrace:
at bno.a(SourceFile:365)
at beq.b(SourceFile:2536)
at beq.a(SourceFile:404)
at net.minecraft.client.main.Main.main(SourceFile:124)

– System Details –
Details:
Minecraft Version: 1.11
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 90333288 bytes (86 MB) / 309772288 bytes (295 MB) up to 1060372480 bytes (1011 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Launched Version: 1.11
LWJGL: 2.9.4
OpenGL: Intel(R) HD Graphics GL version 4.3.0 - Build 20.19.15.4360, Intel
GL Caps: Using GL 1.3 multitexturing.

Steps to Reproduce:
1. Clicking on the server Phanatic
2. ...
3. ...